Oral variations in Australia: why Rock Advertising never crossed

That distinction is the whole page. England enforces written-variation clauses after Rock Advertising; Australia never followed it. But the Australian rule protects a bilateral agreement to vary, not a unilateral direction the contract says must be written. This page sits under Variations in Australia; the paper that keeps the claim alive is on the variation notice and claim templates page.

What was read. Kaloriziko, Liebe v Molloy, GEC Marconi, Bundanoon, White v Philips, Sara Stockham and Mann v Paterson were read on AustLII, and the Victorian Act from the authorised version. Update Constructions was not read. No licensed Standards Australia text was read: AS 4000-1997 cl 36.1 is quoted only where two independent amended public copies agree, and nothing from AS 4000:2025 or AS 2124 appears in quotation marks.

Why Rock Advertising never crossed to Australia

The Australian position is old, and it started on a building site. In Liebe v Molloy [1906] HCA 67 the contract required extras to be ordered in writing, signed by the architect and indorsed by the proprietor. No such orders existed. The umpire found only that the proprietor had such knowledge of the extras as could be inferred from his being constantly on the works. Griffith CJ, for the Court, said the written-order stipulation barred recovery under the contract but "does not exclude altogether the implied doctrine of law that, when one man does work for another at his request, an implied obligation arises to pay the fair value of it". Knowledge alone was not enough: a further inference, that there was an implied contract to pay, had to be drawn. One example the Court gave was an owner standing by and seeing the work done, knowing the contractor expected to be paid for it as extra.

Two features are routinely lost in retelling. The Court did not find a promise; it said one may be inferred, and remitted that factual question to the umpire. And the architect's orders did not bind the owner unless the architect had the owner's authority to order extras.

The modern statement is GEC Marconi Systems v BHP Information Technology. Finn J treated the principle as settled ([215]–[217]): a writing clause does not render ineffective a later oral or implied variation, but it "can have significant evidentiary effect" ([221]). The clause is evidence, not a wall. At [223] he flagged "interesting questions yet to be resolved" for extras under building contracts with writing requirements; the case itself concerned an IT sub-contract.

Rock Advertising took the opposite view in 2018: party autonomy operates up to the point the contract is made, and after that only as the contract allows. Australian courts have been asked about it since, and have not moved.

Bundanoon and White v Philips: the question left open

The two 2019 New South Wales Court of Appeal decisions are often cited together, and misattributed.

• In Bundanoon Sandstone v Cenric Group, Gleeson JA (with whom Meagher and McCallum JJA agreed) recorded at [122] the primary judge's holding that a no-oral-modification clause cannot prevent the parties agreeing orally to vary, noted it was not directly challenged, and found it not necessary to discuss the contrary English view.
• In White v Philips Electronics Australia, Bell P at [42]–[43] found it unnecessary to decide the point, referring back to Bundanoon, while observing, obiter, that such clauses, "even if not necessarily preclusive of oral modifications, provide important context in considering whether the requisite contractual intention to modify or vary a written contract, objectively ascertained, exists".

The "important context" words are Bell P's, not Bundanoon's; several published summaries, including this library's neutral page, attach them to the wrong case.

Bundanoon declined to discuss Rock Advertising; White v Philips does not mention it, and refers only to the question noted in Bundanoon. In Sara Stockham v WLD Practice Holdings [2021] NSWCA 51 at [15], Leeming JA described Rock Advertising as "a decision which has repeatedly been said not to reflect the position in Australia", and, without submissions on the point, proceeded "in accordance with Australian authority". It is not a construction case. NEGATIVE FINDING A search on 26 September 2026 located no Australian appellate decision since 2019 that adopts Rock Advertising, and no High Court decision on the point. (Inference.) Displacing Liebe v Molloy would take the High Court, and nothing on the record suggests an appetite for it.

The equitable route: Update Constructions and estoppel

The second route around a formality is equitable. Finn J in GEC Marconi (at [217]) states it: one party "may so induce or encourage the other's assumption … that the relevant formal requirements need not be complied with, as to be estopped from later setting up those requirements", citing Update Constructions v Rozelle Child Care Centre. Update itself was not read; its contemporaneous case note is headed "Notice Requirements – Estoppel", so (inference) it concerned a notice requirement rather than a written-variation clause.

Estoppel needs more than an instruction. It needs a representation or inducement attributable to the party to be bound, reliance, and detriment. (Opinion.) On a construction job that usually means the Principal, or a Superintendent acting within the authority the Principal gave, doing or saying something that made the contractor reasonably proceed without the paper. A site engineer's "just get on with it" is rarely enough on its own.

AS 4000 cl 36.1: the written-direction gateway

Here is where the Australian permissiveness meets the form. Cl 36.1 (Directing Variations) allows a variation only where directed in writing by the Superintendent and before the Date of Practical Completion. As summarised by HWL Ebsworth, AS 4000:2025 has shortened the clause, making that clear. SINGLE-SOURCE on the 2025 change: of the four firm summaries read, only HWL Ebsworth addresses cl 36.1 directly.

Three conditions, cumulative: writing, the Superintendent, and the pre-completion window.

Is this new? No. Two independent amended public copies of the form family, an AS 4000-1997 tender copy and the AS 4902-2000-based conditions quoted in Kaloriziko, both open cl 36.1 with "The Contractor shall not vary WUC except as directed in writing" and confine the power to direct to before the Date of Practical Completion. The rule was in the 1997 edition; HWL Ebsworth reports that 2025 shortened and clarified it. (The 2025 wording itself was not read.)

What cl 36.1 does, and what it cannot do

Read cl 36.1 against Liebe v Molloy and GEC Marconi, and the analysis has three steps. (Inference, from the authorities above; no Australian decision applying them to AS 4000 cl 36.1 was located.)

1. It closes the contract route. An oral instruction is not an effective cl 36.1 direction. The Superintendent's pricing obligation under cl 36 is not engaged, so there is no contractual valuation to claim.
2. It does not prevent a fresh bargain. Cl 36.1 regulates the Superintendent's unilateral power to direct. It does not, and on the Australian authorities cannot, stop the Principal and Contractor agreeing a variation orally or by conduct. That agreement must itself be a contract: consensus, and consideration.
3. It does not defeat an estoppel where the Principal induced the contractor to proceed.

The risk-shift is the point. A cl 36 claim needs a written direction and a valuation. The two surviving routes need proof of consensus with, or inducement by, the Principal. That is a harder evidential case, run later, with the Superintendent's certificate no longer doing the work.

The Principal-direct-instruction trap

Under cl 36.1 the gateway is the Superintendent. A written instruction sent by the Principal's development manager straight to the Contractor is not a cl 36.1 direction, however clear it is. Two consequences pull in opposite directions.

(Inference.) The trap: a contractor holding that email may wait for a valuation that never comes. Nothing obliges the Superintendent to price it under cl 36.

(Inference.) The consolation: because the surviving routes need the Principal's consent or inducement, an instruction from the Principal itself is better evidence for a bilateral variation or an estoppel than an instruction from the Superintendent would be. Plead it as an agreement with the party to the contract, not as a defective direction.

Cl 7: email directions now count

HWL Ebsworth, Gilbert + Tobin and Colin Biggers & Paisley report that AS 4000:2025 expressly recognises email and electronic service of notices (cl 7(b) and (c), per HWL Ebsworth). (Inference.) A Superintendent's email can be a written direction. Whether a message, a marked-up drawing or an RFI response is a direction to vary is a question of construction, and the author still has to be the Superintendent.

Practical Completion before the certificate: the window can close early

Four summaries (HWL Ebsworth; Gilbert + Tobin; Colin Biggers & Paisley; Swaab, quoting Standards Australia's list of changes) report that the 2025 edition allows Practical Completion to occur before the certificate issues, and one (ACC) reports that the certificate may nominate an earlier date. The sub-clause is given as 35.6 by HWL Ebsworth and 34.6 by ACC. CONFLICT

(Inference.) Put that beside cl 36.1. If the Date of Practical Completion can be fixed earlier than the certificate, a direction issued between actual completion and certification may fall outside the window: the last weeks of a job, when punch-list changes are directed fastest and recorded worst.

Where Storia fits

Every argument on this page turns on the same facts: who directed the work, in what document, and on what date relative to Practical Completion. Storia turns drawings, RFIs, schedules, correspondence and field reports into one source-linked project record, where every answer traces back to the document it came from. Built as the work happens, that record lets a team show whether a written direction from the Superintendent existed before the Date of Practical Completion, or, if it did not, assemble the Principal-level emails and meeting notes that an agreement or estoppel case needs.

Kaloriziko (2025): what it decides, and what it does not

Kaloriziko v Calibre Construction Group (No 2) is a recent New South Wales Court of Appeal decision on variation formality, and it is already being misdescribed. Read from the judgment:

• It is not an AS 4000 case. The contract was a design and construct contract on amended general conditions "in the AS 4902-2000 format". Its cl 36.1, with the Principal's Representative as the directing party, is that contract's wording, not the standard's.
• Approval is not a direction. The developer had approved, but not paid, a consultancy-fee item (V44). The Court held the fees were within the work under the contract, and the approval did not operate as a direction under cl 36.1 and could not price a variation under cl 36.4: "The pricing of a non-variation does not convert it to a variation." As the headnote summarises it ([115], [117]–[118]), approval was no more than an implied admission capable of being displaced by the true contractual position. Credit to the developer: $133,175.
• Strict compliance matters. The Court said the authorities it reviewed "highlight the importance of strict compliance with provisions such as cl 36".
• The practical completion date was not varied. Cl 5(b) of the Formal Instrument said the contract "may be varied only by written instrument executed by both parties". No written variation existed, the documents showing a later date were consistent with clerical error, and "[n]either an oral agreement nor any conduct by the parties supported a variation" ([121]–[124], [127]).

That last point is a finding on the evidence. The Court did not hold that cl 5(b) excluded an oral variation as a matter of law; it found none had been proved. Kaloriziko is therefore consistent with Liebe v Molloy: the door is open, but the contractor still has to walk through it with evidence.

Two corrections to circulating summaries. Only $133,175 of the $3,243,175 reduction concerned a variation; the rest was $210,000 in liquidated damages and $2.9 million on an equitable contribution point about a deed of settlement. And the five items the developer had approved and paid (V1, V7, V11, V13, V21) were held not to be variations, but each was an excluded item payable separately, so the builder kept the money. The "approved variations reversed" headline is wrong. The pricing consequences are on the valuation spoke.

AS 2124-1992 cl 40.1 and cl 46.1: informality allowed, then punished

AS 2124-1992 remains in wide use, and on writing it runs the other way. As summarised by Turtons, cl 23 contemplates directions being given orally as well as in writing, and the prohibition in cl 40.1 (Variations to the Work) attaches its writing requirement to the Superintendent's approvals rather than to directions. So a variation direction under AS 2124 arguably need not be written. SINGLE-SOURCE That guide also reports that under cl 23 a contractor who asks in writing for an oral direction to be confirmed is not bound to comply until it is.

(Inference.) On AS 2124 the fight is evidential (did the direction happen, in what terms, from whom?) rather than legal.

Cl 46.1: the notice trap

Cl 46.1 requires a prescribed notice within a fixed period, failing which the claim is at risk of being time barred. The period is reported as 42 days in two independent sources: Turtons (19 October 2018), reading it "on one interpretation" as running from the Superintendent's direction and calling the clause ambiguous, and a South Australian Housing Trust annexure (February 2023) that amends "42 days" to "28 days". Both are summaries or amendments, not the standard's text. What starts the period is not settled UNVERIFIED: another source runs it from when the Contractor could reasonably have been aware of the claim. Check your contract's cl 46.1 and special conditions.

(Inference.) The combination is the trap. AS 2124 tolerates an oral direction at the front end, and a contractor that treats the oral direction as the end of the paperwork can lose an otherwise good claim at cl 46.1. Carry AS 2124 habits onto an AS 4000 job and the direction fails; carry AS 4000 habits back onto AS 2124 and the direction survives but the notice may not.

Back-to-back: AS 4000:2025 upstream, older conditions downstream

Standards Australia says it will review and update AS 4902-2000, the design and construct form, following AS 4000:2025. [EDITION ALERT] No revised AS 4902 was located as at 26 September 2026, so design and construct documents in use are on the 2000 edition, and many subcontracts sit on older or bespoke conditions.

(Inference.) The mismatch is probably not the bare writing rule: the 1997 form family already required a written direction before practical completion. The mismatches that matter are the ones the 2025 edition added: express email service (cl 7) and a Date of Practical Completion that can precede the certificate. A subcontractor whose document does not carry those terms can have a direction that is valid downstream but not upstream, or a completion window that closes at a different moment on each tier. Draft the flow-down expressly; do not assume the tiers line up.

Mann v Paterson: the restitution fallback, stated correctly

When the variation routes fail, contractors reach for quantum meruit. Mann v Paterson Constructions limits that reach, and is often misstated.

• Where a contractual right to payment had accrued, there is no quantum meruit; the claim is in contract.
• Where restitution is available, the recoverable amount should prima facie not exceed a fair value calculated by reference to the contract price for the relevant work (Nettle, Gordon and Edelman JJ at [215], allowing exceptions; Gageler J at [105], without qualification). Kiefel CJ, Bell and Keane JJ did not decide the point.
• On variations, the Court (all seven Justices) held that s 38 of the Domestic Building Contracts Act 1995 (Vic) prevented a builder recovering in restitution for domestic-building variations not made in accordance with that section.

That third point is Victorian domestic-building law. It is not authority that a builder who breaches a contractual written-variation clause, on a commercial AS 4000 or AS 2124 job, cannot recover in restitution. The general lesson from Mann is the prima facie price ceiling. (Opinion.) On commercial work, restitution for uninstructed variation work is a weak fallback in any event, because the contract usually supplies the juristic reason the claim has to overcome.

Victoria s 13A: can it reach a written-direction clause?

Since 15 April 2026, s 13A of the Building and Construction Industry Security of Payment Act 2002 (Vic) lets an adjudicator, court, arbitrator or expert declare a notice-based time bar provision unfair in relation to a particular entitlement, if compliance "is not reasonably possible" or "would be unreasonably onerous". A declared provision has no effect on the particular entitlement in issue (s 13A(3)(a)), and "continues to have effect in other circumstances or proceedings" arising under the contract (s 13A(3)(b)). The party alleging unfairness bears the onus (s 13A(4)).

A variation claim notice looks like the paradigm case. A written-direction condition is harder. Section 13A(8) defines the provision as one that makes an entitlement "contingent or dependent on the provision of notice by a party", and "notice" includes notice of the time, cost, intention or description of a thing. (Inference.) Whether a Superintendent's direction, or a Principal's approval, is "notice by a party" at all is the question, and it is unresolved. NEGATIVE FINDING No decision applying s 13A to a variation-formality clause was located. The full treatment is on adjudicating the variation account in Victoria; the equivalent Western Australian power and the EOT side are on notice and time bars in Australia.

The strongest case against this page's framing

A careful opponent would say three things.

First, Liebe v Molloy is thinner than its reputation. A 2019 barristers' paper observes that the ineffectiveness of the written-order clause was assumed, not decided. Partly. The Court stated the principle briefly and without contested argument, but it stated it as law and remitted on that footing; it left open only whether a promise was proved. And GEC Marconi treated the point as settled, and none of the 2019 or 2021 appellate decisions departs from it. (Opinion.) The foundation is narrow; the building on it is not.

Second, cl 36.1 is not a no-oral-modification clause at all. It conditions a unilateral power to direct; the NOM authorities concern bilateral agreements to vary. That is correct, and it is this page's point: the Australian rule does not rescue the direction. It rescues a separately proved agreement.

Third, outcomes may look English anyway. Kaloriziko stressed "the importance of strict compliance with provisions such as cl 36" and found no oral or conduct variation proved. Where the only evidence of agreement is a site instruction, an Australian court will often reach the result an English court reaches by rule. (Opinion.) The difference is real but it is evidential: in Australia the contractor with Principal-level emails, minutes and payments can win; in England, after Rock Advertising, that evidence usually does not matter.

For the US, where the answer flips on whether the owner is public or private, see written instruction and waiver in the United States. That link is a comparison; nothing in it is authority for an Australian proposition.

What to do about it

(Opinion, offered as working practice rather than as authority.)

1. Identify the form and the gateway on day one. AS 4000 (1997 and 2025): the Superintendent, in writing, before the Date of Practical Completion. AS 2124-1992: direction may be oral, but diarise the cl 46.1 notice from the direction. Read the executed contract; amendments are the norm.
2. Ask for every oral direction in writing, the same day, addressed to the Superintendent, stating who gave it, when, and what work it requires. The variation notice templates include one.
3. If the Principal instructs you directly, get the Principal's agreement to pay, not just the instruction, and send the Superintendent a copy asking for a cl 36.1 direction.
4. Watch the end of the job. Treat the Date of Practical Completion as capable of being earlier than the certificate, and get late directions in writing before you believe the works are complete.
5. Plead in order: written direction; then agreement with the Principal (Liebe v Molloy, GEC Marconi); then estoppel (Update Constructions); then restitution, subject to Mann's prima facie ceiling. In Victoria, add s 13A where a claim notice was missed.
6. Do not treat an approval as a variation. After Kaloriziko, an approved and priced item that is within scope is still within scope, and payments on account can be revisited.

About this material Library content is general information about construction claim practice, not legal advice. Entitlement, deadlines and procedure are governed by your own contract and by the law of the place the work is performed. Reviewed September 26, 2026 · Report a correction