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Australian Standard contracts are usually heavily amended, so the deadlines that apply are the ones in your special conditions. Under the unamended AS 4000, the key clocks run for 28 days.
Under AS 4000 clause 34.3, the Contractor claims an extension of time within 28 days of when it should reasonably have become aware of the delay, with details of the delay and an estimate of its effect.
Under clause 34.5, the Superintendent assesses the claim within 28 days of receiving it. If the Superintendent does not, the extension of time claimed is deemed granted.
AS 4000:2025, published in June 2025, replaces many fixed deadlines with duties to act as soon as practicable, recognises electronic communication and lets Practical Completion occur before a certificate is issued.
AS 4000 is used for construct-only work and AS 4902 for design and construct, with AS 2124 still found on older and government projects. Some government agencies use their own forms, such as GC21 in New South Wales.
AS 4000 is the Standards Australia general conditions of contract for construct-only work. First published in 1997, it is one of the most widely used construction contracts in Australia, and an updated edition, AS 4000:2025, was published in June 2025.
AS 4000 is for construct-only work, where the Principal provides the design. AS 4902 is for design and construct, where the Contractor takes on design. AS 2124 is an older construct-only form that is still used, with broader grounds for extensions of time and express time bars.
AS 4000:2025 aligns the contract with current law on GST, insolvency and work health and safety, replaces many fixed deadlines with duties to act as soon as practicable, recognises electronic communication, and adds dispute options including a Dispute Avoidance Board.
The Superintendent is appointed by the Principal to administer the contract. They issue directions, assess claims and certify payment, and must act honestly and fairly when assessing and certifying.
Under AS 4000-1997 clause 34.3, the Contractor claims within 28 days of when it should reasonably have become aware of the delay. The Superintendent then has 28 days to assess it, or the claim is deemed granted. Special conditions often change these periods.
AS 4000 has been updated rather than replaced. AS 4000:2025 was published in June 2025, and Standards Australia is also updating AS 4902.
Contract terms vary by edition and are frequently amended. Always check the contract and any project-specific amendments that apply. This guide is general information, not legal advice.
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