Midwives filing a pay parity case could well be just the tip of the iceberg.

LISTEN:  James Sproule talks to Rachel Smalley about the gender pay gap.  

Education union the NZEI says it also intends to take legal action on behalf of education support workers over the gender pay gap.

Mostly women, the workers help kids who have special needs, and are employed by the Education Ministry rather than schools.

The NZEI says the Government's been ignoring the issue for too long.

A report just over six years ago found they were paid as much as eight dollars an hour less than the comparable male-dominated role of Corrections officer.

National Secretary Paul Goulter says there is more than one group within the education sector alone which could take cases.

"[There's] school support staff who we think probably would have a very strong case as well, and maybe even early child hood education teachers, so there's almost like a line up in the education sector."

Mr Goulter, says the Government's pointed to the bargaining table as the place to sort it out, but there's been no real movement.

"I think it's appauling that the Government refuses to acknowledge these gaps and fix them. They have, we believe, a duty to do that."

Paul Goulter hopes the Government sees sense and tries to negotiate a solution.