The first education pay round of the financial year has seen more mistakes by Novopay, most of them due to a single bug that caused 1480 staff to receive overpayments of $65 each, a total of $92,000.
Novopay minister Steven Joyce said "The mistake is a reminder of the challenges in remediating a very complex pay system".
Joyce said he had been advised that it was a "one-off event that has been corrected".
In this pay round, 2.14 percent of staff reported mistakes, up from 0.43 percent last time. Until this round, the number of complaints and notifications had been steadily reducing.
If the single error causing the large number of overpayments was removed, complaints and notifications would have been 0.55 per cent of staff, said Joyce.
The issues this time break down to 39 staff not paid, 1647 overpaid, and 206 underpaid. Affected staff were from 386 schools or 15.7 per cent of schools in the payroll system.
Meanwhile, Talent 2, the company behind Novopay, will be called to the headmaster's office again tomorrow.
Acting Secretary for Education Peter Hughes is expecting a report by the end of Friday, on how the company plans to prevent another mistake like the one early in the week when private information was emailed to the wrong people.
The breach is the latest in a string of similar incidents including at Immigration NZ, Work and Income, ACC and Inland Revenue
Novopay is also facing a Ministerial Enquiry and has been subject to a Technical Review in which it was found not fit for purpose.