The Mondayisation of Anzac Day has left a few businesses scratching their heads.

Anzac Day is one of just three-and-a-half days a year when almost all shops must be closed under the Shop Trading Hours Act, which means most businesses need to remain closed until after 1pm.

But this year, Anzac Day falls on a Sunday, meaning businesses will need to work out how to pay staff across the 25th of April... and the Monday that follows.

Retail NZ managing director Greg Harford says his organisation has been inundated with calls from confused businesses owners over how to manage the spread-out public holiday.

'Depending on how your rostering works, you might end up paying holiday pay for two days,” he said.

Harford said he completely supported the Anzac holiday, but he believed the law probably needed more clarity to help businesses navigate the rules correctly.

While stores have to close until 1pm on April 25, the same does not go for the Monday.

Stu Lumsden, Labour Inspectorate national manager said the Mondayisation applies to employees, not trading restrictions.

'As trading restrictions are not Mondayised, shops only need to close until 1pm on April 25,” he said.

'They can still open on Monday April 26, even if the holiday is Mondayised for their employees.”

If your employee normally works on Sunday

If a worker normally works on Sunday, April 25, then they get the holiday benefits for those hours.

That includes time-and-a-half for the hours they work on the day and an alternative holiday – as well as pay for any they don't work, if their place of work is closed.

If an employee who usually works on a Sunday doesn't actually work at all and takes it as a holiday, then they get paid as a public holiday, but they don't get the alternative holiday.

If your employee works on Monday

Staff normally rostered on Monday are entitled to normal holiday entitlements.

This means, they can either take the day off or time-and-a-half and an alternative holiday.

But what happens if they work both days?

An employee is only entitled to one day treated as a public holiday.

If an employee is normally rostered on for both Sunday and Monday, and works both days, then it is the Sunday that applies for the holiday entitlements.

What about casuals?

Casual employees working on a public holiday are entitled to be paid at time-and-a-half. If their employment agreement is a casual employment agreement, but they have a pattern of work and the public holiday is a day that would otherwise be a working day for them, they are also entitled to an alternative holiday.

If an employee on a casual employment agreement doesn't work on Anzac Day because their workplace closes that day, but it is a day that would otherwise be a working day for them, they should still be paid for that day.

However, casual employees who only work on public holidays, or who work on a public holiday where it is not otherwise a working day for them, should be paid at time-and-a-half but are not entitled to an alternative holiday.

Debrin Foxcroft/Stuff