Prevention principle and time at large in Australia

That reframing matters more than any single case on this page. In England the contractor argues prevention to destroy the completion date outright. In Australia the contractor argues that the Superintendent was obliged to extend. A narrower, more predictable and much easier remedy to win, and one that keeps a date alive rather than setting one at large. Time at large is correspondingly rare. Everything below rests on a single source note, and a verification caveat applies to nearly all of it: AustLII, NSW Caselaw, Jade and the High Court's own site all returned 403 during the research behind this page, so treat the Australian case law here as secondary-sourced and unverified pending primary-text confirmation. For the wider framework, start at extension of time in Australia.

The orthodox position: prevention does not rescue a procedural failure

The starting point is unhelpful to contractors who had a mechanism and did not use it. In Turner Corporation Ltd (Recvr & Mgr Apptd) v Austotel Pty Ltd (1994) 13 BCL 378 (NSWSC, Cole J), a contractor that had an available extension-of-time mechanism but failed to use it was not "prevented". The prevention principle does not exist to rescue a contractor from its own procedural failure. It answers a different question, whether the principal's conduct destroyed the mechanism, not whether the contractor bothered to operate it. That is the prevailing position across Australian jurisdictions, and it aligns with the later English position in Multiplex v Honeywell (No 2).

Gaymark: the only Australian finding, and how confined it is

Set against that orthodoxy is a single outlier. Gaymark Investments Pty Ltd v Walter Construction Group Ltd (1999) 16 BCL 449, [1999] NTSC (Bailey J) reached the contrary result: the contractor's failure to lodge EOT applications within a contractual time bar, for delays the principal caused, put time at large and defeated the liquidated damages claim entirely.

Its current standing is doubtful and effectively confined. Gaymark has been widely criticised, and was rejected in England by Jackson J in Multiplex Constructions (UK) Ltd v Honeywell Control Systems Ltd (No 2) [2007] EWHC 447 (TCC) at [103]. But no Australian appellate court has expressly overruled it. It remains a first-instance Northern Territory decision that has been distinguished rather than disapproved, and it retains argumentative value in one specific configuration: a contract with a time bar and no unilateral EOT power. Because most Australian standard forms do have that power, the configuration is rare, which is precisely why Gaymark has never had to be overruled outright. It has simply had nothing to bite on.

The doctrine that actually governs: the unilateral power

Where Gaymark is the exception, the following line of authority is the rule. Peninsula Balmain Pty Ltd v Abigroup Contractors Pty Ltd [2002] NSWCA 211, (2002) 18 BCL 322 held, on AS 2124, that the Superintendent's unilateral extension-of-time power must be exercised honestly and fairly, and that the Superintendent was required to grant an extension even though the contractor was out of time. 620 Collins Street Pty Ltd v Abigroup Contractors Pty Ltd (No 2) [2006] VSC 491 follows the same line: the independent certifier owes a duty to act honestly and fairly in exercising EOT powers.

Probuild Constructions (Aust) Pty Ltd v DDI Group Pty Ltd [2017] NSWCA 151 sharpens the point into a rule that decides money. On an amended AS 4303-1995 subcontract, the subcontractor completed 144 days late without timely EOT claims, and the head contractor sought to set off liquidated damages. The Court held that to claim liquidated damages, the head contractor was obliged to exercise its unilateral power to extend time for delays it had itself caused. It indicated an implied duty of good faith in exercising the discretion, but confined that duty to the prevention rationale, meaning it obliges extension only for delays the principal actually caused, not an at-large fairness obligation running in every direction.

A principal who declines to use the unilateral power for delays it caused loses the liquidated damages that power was meant to protect.

V601 Developments: the duty enforced at its sharpest

V601 Developments Pty Ltd v Probuild Constructions (Aust) Pty Ltd [2021] VSC 849 (Digby J) is the modern high-water mark. The Superintendent was found to have colluded with the principal. The liquidated damages certificates were set aside and the LD claim failed wholly. Acceleration costs were recovered, though the court expressly declined to treat the EOT refusal as a "direction". And the EOT clause was held to require retrospective delay analysis, a contractual limb that other Australian methodology cases lack.

V601 is the case to cite when the Superintendent has not been independent. It converts the Peninsula Balmain duty from a principle into an actual remedy: not just a statement that the discretion must be exercised honestly and fairly, but a court prepared to set aside certificates and defeat an LD claim wholly where it was not.

The device principals use to neuter the duty

The honest-and-fair architecture has an obvious point of attack, and principals have found it. Queensland TMR contracts provide, at clause 2.2(j), that absolute discretions need not be exercised for the contractor's benefit. That is a direct attack on the whole Australian EOT architecture, which rests on the unilateral power being exercised honestly and fairly. Remove the obligation to consider the contractor's interest at all, and the Peninsula Balmain duty has little left to bite on.

The same device succeeded in Growthbuilt [2021] NSWSC 290 and CMA Assets [2015] WASC 217, and it appears in amended AS forms more broadly. It is arguably the single most consequential amendment a principal can make to an Australian EOT regime, and it is the first thing to look for when reading an executed contract rather than the printed standard form.

Time at large: and a widely repeated mis-description

Only Gaymark has ever found time at large in Australia. It is a first-instance Northern Territory decision, criticised, distinguished rather than disapproved, and never expressly overruled.

One case is regularly cited alongside it and should not be. SMK Cabinets [1984] VR 391 is widely mis-described as a time-at-large case. It is not. It disallowed liquidated damages prospectively from the act of prevention. It did not set time at large, and it should not be cited for that proposition.

And the doctrine has been declined repeatedly since Gaymark: Growthbuilt at [80]. CMA Assets [2015] WASC 217, and Bensons [2021] VSCA 69. Holding that "the touchstone must be the terms of the contract".

The Australian answer to "is time at large?" is almost never, and the contract is where the argument is won or lost.

Comparative. The Australian row states first-instance and intermediate appellate authority. Case law throughout this corpus is treated as secondary-sourced and unverified.

The interaction with AS 2124's concurrency bar

Under AS 2124-1992, clause 35.5, the contractor gets no extension of time to the extent delays are concurrent. But Probuild v DDI Group holds that a principal must exercise its unilateral power for delays it caused if it wants its liquidated damages.

Where the principal caused part of a concurrent delay period, those two rules pull in opposite directions. The form denies the EOT. Probuild obliges the extension. That interaction is under-litigated and is a genuine open question, best flagged to a client rather than resolved with false confidence. See concurrent delay in Australia.

The statutory layer now sits on top

From 15 April 2026 in Victoria and since 1 August 2022 in Western Australia, a notice-based time bar. Including an EOT time bar affecting a payment or security entitlement. May be declared unfair and of no effect where compliance "is not reasonably possible" or "would be unreasonably onerous".

This substantially reduces the need for a prevention argument in those two states, because the contractor can attack the bar directly rather than arguing that the principal's conduct destroyed the completion date. It does, by statute and with a structured test, roughly what Gaymark tried to do at common law. See notice and time bars in Australia.

Three practical consequences

The reframing from prevention to unilateral power carries through into how a dispute is actually run.

First, the contractor's first argument is the discretion, not the doctrine. Ask what the Superintendent knew, when it knew it, and whether the power was considered at all. Not whether the principal's conduct was, in the abstract, an act of prevention.

Second, certifier independence becomes the battleground. Peninsula Balmain and 620 Collins Street are about the certifier's duty to act honestly and fairly. A Superintendent who acts as the principal's agent rather than as an independent decision-maker in exercising the power is the target, and V601 shows what a court will do once collusion is established.

Third, time at large is correspondingly rarer in Australia than the English case law would suggest. The unilateral power keeps a date alive in the great majority of disputes, which is exactly why Gaymark has stayed a first-instance outlier rather than becoming a live doctrine. There is almost always a power available to make the Gaymark configuration inapplicable.

What this means for how a claim is actually built

None of this removes the value of records. Probuild v DDI Group and V601 both turn on what the Superintendent knew and when, which means the contractor's case is built the same way a prevention case would be built in England: contemporaneous notices, programme updates, and correspondence showing the principal's own conduct caused the critical delay. The difference is what that evidence is used to prove. In England it proves that the completion date has been destroyed. In Australia it proves that a discretion was not exercised honestly, or was not exercised at all. A narrower proposition, but one a court is considerably more willing to find in the contractor's favour, because the consequence for the principal is a recalculated date rather than the loss of the entire liquidated damages regime.

That also explains why the Queensland TMR-style device is worth identifying early rather than late. Where clause 2.2(j)-style wording is present, the contractor's Probuild argument has nothing to attach to. There is no honest-and-fair obligation for the principal to have breached, because the contract says the discretion need not be exercised for the contractor's benefit at all. In that configuration the contractor is thrown back onto Gaymark's narrow ground: a time bar, and effectively no unilateral power worth the name. It is one of the few situations in which Gaymark becomes directly relevant again, rather than a historical curiosity.

The synthesis

The presence of a unilateral EOT power, honestly exercised, is what saves the principal's liquidated damages entitlement, and a principal who declines to use that power for its own delays loses them. That is the practical rule that does almost all of the work on an Australian project, and it is why the prevention principle proper, and time at large with it, comes up so rarely. A contractor arguing prevention in Australia is usually running the second-best argument. The first is that the Superintendent was obliged to extend.

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 1, 2026 · Report a correction