Prime Minister John Key says ongoing mistakes in the new teacher pay system are unacceptable and the company responsible will face financial penalties if they aren't fixed.
Novopay has been plagued with problems since it was introduced in August with errors in more than 8000 teachers' pay.
Yesterday it was revealed personal information and bank account details for hundreds of teachers had accidentally been made available to staff at Auckland's Marshall Laing Primary School.
Responsibility for the $30 million new system, provided by Talent 2, has been handed from Education Minister Hekia Parata to Associate Education Minister Craig Foss.
As of Saturday there were 1500 outstanding errors and the Education Ministry has ordered Talent 2 to fix the problems by Wednesday.
Labour has called on Parata to take over oversight for Novopay, saying Foss is "clearly out of his depth".
But Key this morning backed the associate minister.
"The issue isn't with the associate minister in this case, Craig Foss is doing a good job," he told TVNZ's Breakfast programme.
"The issue is with the provider."
Key said there were 60,000 teachers and their pay roll system was complex, with three layers of rates teachers could be paid at.
However, he said the mistakes were not good enough.
"Talent 2 worked on that for a long time, it's a big project. The Government's paid them a lot of money and they should have got that all right.
"A lot has been fixed up but not enough. So to those teachers who haven't been paid and are owed back-pay, that is unacceptable because people rely on their pay to pay their bills."
Although the prime minister said he couldn't comment on the Government's contract with Talent 2 for commercial reasons, they company was likely to face a financial penalty if errors weren't resolved.
"The pressure has to come on there and there is all sorts of ways we can hold them to account. They are under no illusions from the Government, and from the minister, what is expected of them."
Talent 2 is an international human resources and pay roll systems company with offices all over the world.
No one from the company was immediately available for comment.