What AS 4000 actually is

AS 4000 is a general conditions of contract published by Standards Australia. It sets out the rules between two parties for the length of a construction job: how the work is instructed, how time is managed, how you get paid, who decides disputes, and what happens when something goes wrong. It is designed as a fair, balanced starting point, which is exactly why main contractors and principals so often amend it before it reaches you.

A key figure in AS 4000 is the Superintendent. This is the person who administers the contract day to day, assesses claims, issues payment certificates and grants extensions of time. On many jobs the Superintendent works for the party above you, so knowing what they can and cannot do under the contract matters.

AS 4000 vs AS 4901: which one are you signing?

This trips up a lot of subcontractors. AS 4000 is the head contract, used between the main contractor and the principal. AS 4901 is the companion subcontract form, written to sit underneath AS 4000 so the terms line up. As a subcontractor you will usually be signing AS 4901 (or an amended version of it), not AS 4000 itself.

Why care about the head contract you are not a party to? Because obligations flow down. Notice periods, time bars and claim requirements from the head contract are frequently mirrored, or made stricter, in the subcontract you sign. If you have only read your subcontract and not asked how it connects upstream, you may be agreeing to timeframes set by a contract you have never seen.

We cover the subcontract side in detail in what to check before you sign an AS 4901 subcontract.

The clauses that matter most to subcontractors

You do not need to memorise the whole document, but a handful of clauses decide whether you keep your money when a job goes sideways:

  • Time and extensions of time (Clause 34). This clause governs delay notices and EOT claims. In the standard form you must give the Superintendent written notice promptly, and an EOT claim within a set number of days of becoming aware of the cause. Miss the window and your entitlement can be at risk.
  • Payment (Clause 37). Sets out progress claims and the time the Superintendent has to certify payment. Note the standard form does not itself deal with state Security of Payment laws, which apply regardless of what the contract says.
  • Variations. How changes to your scope are instructed, priced and recorded. Verbal directions and unpriced variations are where subcontractors most often lose money.
  • Security and retention. Retention amounts, bank guarantees and when your security is released. This is real cash held against your work.
  • Latent conditions. What happens when site conditions differ from what you priced, and the notice you must give to preserve a claim.

Whichever clause applies, the deciding factor is usually your records. See the subcontract clauses that quietly shift risk onto subcontractors for the amendments to watch.

What changed in AS 4000:2025

The 2025 revision keeps the familiar structure but modernises the detail. The changes most relevant to people on site include:

  • Consolidated definitions and simplified language, with all definitions now grouped together to reduce ambiguity.
  • Updated provisions for GST and tax invoices, and Personal Property Securities Act (PPSA) clauses covering security interests in materials and plant.
  • Work Health and Safety updates, including clearer wording around appointing a principal contractor.
  • Modernised dispute resolution, with a staged path from negotiation through mediation, expert determination or a dispute avoidance board before arbitration or litigation.

Because the update is still working through the industry, you may be handed either the 1997 or the 2025 version, and either one may be heavily amended. Check which edition your contract is based on and read it on its own terms rather than assuming it matches the standard.

The real risk is the amendments

The standard AS 4000 is reasonably even-handed. The version that reaches a subcontractor often is not. Main contractors run large commercial teams whose job is to tighten the notice and claims regime in their favour, and the most common changes tighten time bars, expand set-off rights, and shorten the windows you have to claim. A clause that looks harmless can quietly convert a genuine entitlement into a lost one because a notice was a day late.

This is why documenting delays and costs as they happen matters so much. Our clause-check tool and free calculators can help you spot notice requirements and price a delay before it becomes a dispute.

A quick pre-signing checklist

  1. Confirm which form and edition you are signing: AS 4901 subcontract or AS 4000, 1997 or 2025.
  2. Find every notice and time-bar clause, and write the deadlines somewhere your site team will actually see them.
  3. Check how variations must be instructed and priced, and whether verbal directions count.
  4. Read the payment and security clauses: when you claim, when you are certified, and when retention is released.
  5. Compare the subcontract against the head-contract obligations flowing down to you.
  6. Get anything you do not understand reviewed before you sign, not after a dispute starts.

You cannot always change the contract you are handed, but you can go in with your eyes open and your record-keeping ready. If a delay does hit, keeping strong delay records from day one is what turns a clause in your favour into money you actually recover.