The primary teachers' union is angry that the Ministry of Education waited 18 months to publish a report on gender equity in schools.
The ministry this week published its Pay and Employment Equity Review, which has evidence of gender inequities for female teachers, but only after an Official Information Act request.
The review says some schools may be treating their female employees unfairly.
It says some support staff do not get pay rises on time and the work of cleaners and teacher aides is undervalued.
The review also found female teachers are disadvantaged in career advancement and don't receive the same rewards as men: 82% of primary teachers are female, but only 45% of principals in the sector are female.
In secondary schools, women account for 58% of the teaching staff, but only 29% of principals.
The primary teachers union, the New Zealand Educational Institute, says the report was completed 18 months ago and should have been published earlier.
National secretary Paul Goulter says the report highlights important issues for women in terms of career advancement and rewards.
He says it shows very bad conditions for school support staff and also raises issues concerning the place of women in senior roles.