Business day (Australian building law)
A 'business day' under Australian SOP Acts excludes weekends, state public holidays, and (Vic) the Christmas-New Year shutdown. The unit every SOP deadline counts in.
Ask Chalkline about this →Business day in Australian building law is the unit by which statutory deadlines are counted under the Security of Payment Acts, the Home Building Act warranty clauses, and the various statutory demand provisions. The general rule is consistent across states (verified 2026-05-16):
A business day excludes:
- Saturday and Sunday.
- Public holidays declared in the state or territory where the act is to be done.
Some jurisdictions add specific industry-shutdown windows to the exclusion list. The clearest example is the Vic Building and Construction Industry Security of Payment Act 2002, which historically excluded the construction industry shutdown period (typically 22 December to 10 January, varies year-to-year) from the business-day count. Vic’s recent reform (15 April 2026) retained this carve-out.
State-by-state exclusion summary:
| Jurisdiction | Excluded days |
|---|---|
| NSW (SOP Act 1999) | Saturdays, Sundays, NSW public holidays |
| Vic (SOP Act 2002) | Saturdays, Sundays, Vic public holidays, annual industry shutdown (~22 Dec to ~10 Jan) |
| Qld (BIF Act 2017) | Saturdays, Sundays, Qld public holidays |
| WA (SOP Act 2021) | Saturdays, Sundays, WA public holidays (Schedule 1 definitions) |
| SA, Tas, NT, ACT | Saturdays, Sundays, state-specific public holidays |
Why this matters in practice:
- Payment claim and schedule windows are in business days. A payment claim served on 23 December in Vic (the start of the shutdown) may have its payment schedule window not start until 10-11 January. Builders who count calendar days miss the actual window.
- Adjudication application deadlines are in business days. The 65-working-days NT SOP window or the 10-business-days NSW window can run materially longer than the calendar gap suggests across a holiday period.
- Public holidays differ by state. A Vic builder claiming under a Qld project counts business days against Qld holidays, not Vic ones.
- Practitioner shortcut: count workdays Mon-Fri, deduct national plus state public holidays, deduct Vic Christmas shutdown if applicable. Conservative practitioners count one extra day if uncertain.
Common errors to avoid:
- Counting weekends as business days (basic error, occasional).
- Not excluding the state-specific public holiday (Sept Family and Community Day in ACT, May Day in NT, Royal Show Day in WA, etc.).
- Forgetting Vic’s Christmas-New-Year industry shutdown.
- Counting against the wrong state’s holidays (mixed-jurisdiction project).
Also known as: working day; SOP business day; statutory business day.
Category: Contracts & commercial.
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Last updated: 2026-05-16. Verified: 2026-05-16. Quarterly review for currency.