The number of Ministry of Education staff earning six-figure salaries rose by more than 25 per cent in the last financial year.

The ministry has been under fire for ongoing problems with the Novopay payroll system and controversy over the Christchurch schools' overhaul.

Education Secretary Lesley Longstone announced her resignation last month.

Yesterday, it was revealed that the ministry was hiring external consultants to carry out basic functions.

Documents also show that the number of staff earning more than $100,000 at the ministry rose from 151.65 fulltime positions in 2007/08 to 261.83 in 2011/12.

During the same period, the total number of staff fell by more than 120 fulltime positions.

The number earning more than $100,000 in 2011/12 increased from 208.37 the previous year.

Meanwhile, the number of staff seconded to ministerial offices doubled between 2008/09 and 2011/12.

The total cost of servicing ministerial offices in 2011/12 was $948,175.

Labour MP Chris Hipkins said the salary increases for those at the top were "a bit rich" when those on lower salaries were being told there was no money for pay rises.

"Given how poorly the Ministry of Education has performed in the past few years such a significant increase in the number of staff earning such big salaries seems particularly hard to justify."

A ministry spokeswoman said the proportion of the fulltime-equivalent workforce earning more than $100,000 had increased on average less than 1 per cent a year over the past five years.

The figures also included termination payments and allowances. The increase was due to factors including career progression and strengthening of professional and operational support roles.

- © Fairfax NZ News