More than 6000 support staff in schools are being paid less per week because of a once-in-a-decade payroll change.

Some say they are struggling to pay their bills as a result of the change, under which they are earning the same total income but spread over 54 weeks instead of 52 weeks. They say they are going into debt or skipping doctor's visits and other costs.

The Ministry of Education has defended the payroll change, saying no one is being underpaid and that employees were warned in advance.

Denise Murray, an officer manager at May Road School in Mt Roskill, said she was getting $63 less each fortnight.


"This is a lot for me. I'm on my own and I pay $400 a week rent. I can't afford the dentist or ... or payments on my [$2000] car. I've overdrawn my bank twice this year already.

"I've still got my power, my phone, my rent, but I don't have luxuries. When you're struggling and don't have savings it's a slap in the face."

Support staff in schools, most of whom are teacher aides, are paid for 40 weeks of the year but they can choose to "annualise" their pay days over 52 weeks. Because 52 weeks equals 364 days, the leftover day each year adds up to an additional fortnight, or an additional pay period, every 11 years.

To compensate for this, the school payroll provider Novopay is paying annualised workers in 27 fortnightly pay days this year instead of the usual 26 pay days.

"This means that staff pay will be slightly lower each fortnight, but there will be an extra pay cycle which will bring the total annual pay up to the same amount," said the Ministry of Education's head of the education infrastructure service, Jerome Sheppard.

"Staff who choose to have their pay annualised still receive their full pay and entitlements. Everyone is paid for the hours worked, at the rates set out in their agreements."

Mr Sheppard also said annualising pay was "entirely voluntary" and that staff were notified in November.

New Zealand Education Institute (NZEI) national secretary Paul Goulter said support staff chose to annualise their pay because many of them were on the minimum wage and it made it easier to budget. Some staff were required by Work and Income to be paid fortnightly to get access to support payments. Even a tiny change in pay packets could make life difficult, Mr Goulter said.

NZEI estimates support staff are paid an average of 3.7 per cent less per week.

The union is taking the issue to the Employment Tribunal next month because it says the changes breach its collective contract.