Guide
How to Calculate the Due Date for a Payment Claim in NSW
The due date drives interest, suspension rights and every deadline after it. Here's how to work it out correctly.
Check your contract first: most commercial contracts set their own due date. Where a contract is silent, the Act's fallback provisions apply, and getting this date right matters because interest, suspension rights and later deadlines all flow from it.
Getting the due date wrong on a payment claim can cost you weeks, or your footing in a later dispute. Under the Building and Construction Industry Security of Payment Act 1999 (NSW), the due date is not simply when you would like to be paid. It is a defined trigger that determines when interest starts running, when you can suspend work for non-payment, and how later deadlines in the process are calculated.
What "due date" actually means under the Act
The due date for a progress payment is the date by which the claimed amount becomes payable. It is distinct from the date you serve the payment claim, and distinct from the payment schedule deadline a respondent has to formally dispute it. Confusing these three dates is one of the most common early mistakes we see.
Where the contract specifies a due date
Most commercial construction contracts set their own payment terms, for example payable within a fixed number of days of a valid invoice, or a set date each month. Where the contract deals with the matter, that contractual date generally governs, subject to the Act overriding unfair time-bar and "pay when paid" style provisions that try to make payment conditional on events outside the claimant's control.
Where the contract is silent
If a construction contract does not provide for a due date, the Act supplies a fallback timeframe. The precise statutory default has been the subject of legislative amendment over the years, so if your contract does not clearly deal with payment timing, this is exactly the kind of detail worth confirming against the current, in-force version of the Act before you rely on a calculated date.
Why the exact date matters
The due date affects when unpaid amounts start accruing interest at the rate prescribed under the Act, your ability to suspend work for non-payment (which generally requires the amount to be overdue), and how later deadlines in the payment claim and adjudication process are calculated. Because so much downstream timing depends on this one date, an error here tends to compound rather than stay contained.
How this applies across NSW
Sydney and Western Sydney construction contracts
Head contracts and subcontracts on major projects across Parramatta, the Hills district and Blacktown growth corridors typically run on standard industry contract forms with detailed payment schedules built in, which usually makes the due date a matter of reading the contract correctly. For our broader construction law services in these areas, see Archer Lawyers' Parramatta, Hills district and Blacktown pages.
Regional NSW
Smaller regional builders and subcontractors around Newcastle, Wollongong and the Central Coast are more likely to be working under a short-form or verbal contract, which is exactly when the statutory default provisions become the operative rule rather than a fallback that never gets used. For our broader construction law services in these areas, see Archer Lawyers' Newcastle, Wollongong and Central Coast pages.
Frequently asked questions
Is the due date the same as the payment schedule deadline?
No. The due date is when payment becomes payable. The payment schedule deadline is the separate, shorter window a respondent has to formally dispute a claim. The two are calculated differently and confusing them is a common error.
Can a contract set any due date it likes?
Not entirely. The Act overrides contract terms that try to unreasonably delay payment or make payment conditional on events outside the claimant's control, such as the head contractor being paid first.
What happens if I get the due date wrong?
Working from an incorrect due date can throw off your interest calculation and your assessment of when you're entitled to suspend work. It rarely invalidates a claim outright, but it can weaken your position if challenged.
Does the due date change if the payment claim is disputed?
No. The due date is fixed by the contract or the Act. A dispute over the amount doesn't move the due date, though it does open the payment schedule and, potentially, the adjudication process.
Who do I ask if my contract's payment terms are unclear?
Get advice before you act on an assumption. A short review of the payment clause against the Act is usually enough to confirm the correct date with certainty.
If you're not confident about the due date on a current or upcoming claim, get it checked before you rely on it. Contact our team for a free assessment.