An audit has found that 1776 new teachers were paid below the legal minimum wage while officials assessed their qualifications.
The number, found by the Auditor-General, is far greater than the "small number" of teachers which the Ministry of Education had already admitted to paying below the minimum wage after the minimum was raised to $17.70 an hour on April 1.
The audit has found that:
• 655 current teachers were affected from April 1 this year and received back-pay to bring them up to the new minimum on May 8.
• A further 845 current teachers were already being paid below the previous minimum wage of $16.50 an hour before April 1, and received back-pay for arrears on June 19.
• Another 276 teachers were paid below the legal minimum before April 1 and are no longer teaching. They "will receive a back-payment as soon as possible, recognising that the ministry or Education Payroll Ltd might not have current contact information for those people".
The Auditor-General's sector manager for schools, Jane Rogers, told National MP Nikki Kaye that her office "cannot provide a legal ruling on whether the ministry and EPL have complied with the minimum wage legislation".
But Kaye said it was clearly "a very serious situation".
NZ Educational Institute president Lynda Stuart said she was surprised at the high number teachers affected.
"I hadn't realised that it was that large," she said.
"Obviously we don't ever want to see this happen again for any teacher, let alone those who are new to the profession. It's good that they have got back-pay, but that doesn't compensate for the trauma and hard times they have been through."
The law breach occurred because the pay scales for teachers whose qualifications have not yet been assessed were last negotiated several years ago, before the latest pay increases that were finally agreed to last month after a series of strikes over the past year.
The large numbers indicate that it has affected both newly trained NZ teachers and many of the more than 200 overseas teachers who were recruited to meet a critical teacher shortage this year.
Manurewa Intermediate School principal Iain Taylor, who hired five overseas teachers at the start of this year, said several of them were paid less than the minimum wage initially.
"It's unfortunate salary assessments take so long once lodged, as it takes time to get an Ministry of Education employee number and then open a bank account and get an Inland Revenue Department number," he said.
"So why can't the ministry pay what is estimated on the visa form we have to complete long before the teacher arrives, so use that figure first and once formal assessment is completed then the salary can be rejigged? Although having said that, the estimate tends to be very accurate anyway."
Rogers told Kaye that the ministry said "the appropriate controls were not in place to recognise and increase teacher rates in the payroll system in line with annual minimum wage adjustments".
"We understand that, from May 8, 2019, controls were put in place to ensure that all teachers are paid at least the minimum wage from April 1, 2019," she said.
"The ministry has also confirmed that controls were already in place for other school employees to ensure that they are paid at, or above, the minimum wage.
"The ministry and EPL have plans to formalise the process for ensuring that teachers are paid at, or above, the minimum wage before the next minimum wage adjustment.
"In our view, all of those controls should have already been in place. It is the ministry's responsibility to have controls in place to ensure that it is complying with all relevant legislation."
She said EPL's agreement with the ministry included a requirement to assess new teachers' qualifications and experience to determine their salaries within 15 working days of receiving all the necessary documents.
"The ministry told us that there were three salary assessments during 2018/19, out of about 8300 processed annually, that were not completed within 15 working days," Rogers said.
"It has also told us that it is working with the NZ School Trustees Association to encourage schools to start the salary assessment process before a teacher starts work."
Stuart said that was not always possible during the current teacher shortage, which has forced some principals to ask new teachers to start work immediately before their documents could be assessed.
But she said teacher training institutions could get the paperwork under way before new teachers started work.
The ministry's head of infrastructure Kim Shannon said controls were now in place to ensure that all school employees were paid at least the legal minimum wage.
"We acknowledge again that this underpayment was not acceptable, it should never have happened, and we regret that it occurred," she said.
"The majority of affected teachers have received their back pay. Priority was given to teachers who are still teaching because they are on the schools payroll and we have their current personal information.
"We are arranging back pay for the remaining teachers, who are no longer teaching, as soon as is practically possible, once we contact them to verify their information."