Teachers doubt the Government's ability to fix the error-ridden Novopay system and want a deadline set for putting it right.
Senior cabinet minister Steven Joyce, put in charge of it by Prime Minister John Key, on Thursday announced a ministerial inquiry and a technical audit of the teacher pay system.
He's also talking to Datacom, the company which supplied the previous system, and isn't ruling out scrapping Novopay.
But Mr Joyce says it has to stay in place for the time being because of upcoming teacher pay periods.
He has a remediation plan which includes accelerated software stabilisation, monitoring and improved customer service.
The primary teachers union, NZEI, says its members have had enough.
"Steven Joyce's plan to fix Novopay is a step in the right direction but a deadline for fixing the beleaguered pay system must be set," said NZEI president Judith Nowotarski.
"Principals and school administration staff have put in long hours to sort this mess out so we are still sceptical and want a time limit to fix it - there may be a plan now but it's cold comfort to our members who are still suffering."
Labour leader David Shearer says a ministerial inquiry is a way of pushing the problem under the carpet.
"Novopay should have been road tested before it was rolled out and that's why we're in this situation," he said.
The party's acting education spokesman, Chris Hipkins, says there should be a full and independent inquiry.
Associate Education Minister Craig Foss, who was stripped of responsibility for Novopay in a cabinet reshuffle earlier this month, says he was advised to sign off on the system despite being aware of some "minor" bugs.
Ministry of Education officials and Novopay's board recommended the sign off, he said.