Reviewed August 2026

12-hour shifts and rotating rosters: how the hours add up

A twelve-hour shift is legal under the equivalent working time system. The limits do not disappear — they move from the day to the settlement period, which is exactly where hours go missing.

Why twelve hours is allowed at all

The equivalent working time system lets the daily norm be extended, commonly to twelve hours, in exchange for shorter days or extra days off elsewhere in the same settlement period. Warehouses, factories and rotating rosters run on it.

The average still has to come out at forty hours a week across the period. A long shift is not overtime by itself — it is overtime when the average is exceeded, or when you work beyond what your roster said for that day.

What does not change on a 12-hour roster

Eleven uninterrupted hours of rest after every shift.
Thirty-five uninterrupted hours of rest each week.
An average of forty hours a week over the settlement period.
Forty-eight hours as the average weekly ceiling including overtime.

When a long shift becomes overtime

Two things make it overtime: working past the hours your roster set for that day, and exceeding the average norm once the settlement period closes.

Work on a day that was scheduled as your day off carries the 100% supplement, as does night and Sunday work. Being on a twelve-hour roster does not reduce any of those rates.

Keeping a rotating roster honest

Photograph or save the roster when it is published — it is the baseline you compare against.
Record what you actually worked each day, including the shift that ran long.
At the end of the settlement period, add your hours and compare with the norm.
Raise the difference in writing before the next period absorbs it.

Common questions

Is a 12-hour shift legal at all?

Yes, under the equivalent working time system, provided the average across the settlement period stays at forty hours a week and the daily and weekly rest periods are kept.

My shift crosses midnight. How is it counted?

As one shift. Splitting it across two calendar days is the most common way hours and night supplements get lost on rotating rosters.

They called me in on my day off. What is that worth?

Work on a scheduled day off carries the 100% supplement, or the employer must give you another day off instead. Your ordinary pay for the hours worked is due either way.

Can they change the roster at the last minute?

A roster should be made known in advance, and changing it constantly to avoid overtime is an abuse of the system rather than a feature of it. Your saved copy of the original roster is what makes the change visible.

This page explains the general rules and is not legal advice. Your contract, collective agreement or work regulations may set terms more favourable than the statutory minimum. For a dispute, the National Labour Inspectorate (PIP) advises workers free of charge.