UPDATED 5.36pm: Pay us according to our experience - not according to our gender.

College of Midwives Chief Executive Karen Guilliand speaks to Mike Hosking about the issue

That's the call from the College of Midwives, in what could be the biggest equal pay challenge ever filed in New Zealand.

They claim women who work as midwives earn less than men in similar life-saving roles.

College chief executive Karen Guilliand said midwives are paid in flat-fee modules, regardless of how much experience they have.

"It doesn't really matter if you're a new practitioner or if you've been practising for 20 years - your module remains the same."

"The midwives have to actually pay other people out of their pay for the work they do - for instance if they are sick, they have to pay the other midwife."

Papers are due to be filed in the High Court today, claiming pay issues are gender discrimination.

Health Minister Jonathan Coleman said the first he'd heard of it was media reports, but he's going to take advice on the issue.

The Pay Equity Challenge Coalition is applauding the College of Midwives' move.

PECC spokesperson Angela McLeod said they are keen to work with the College in their fight for equity.

"It's time for change, and we're really pleased that the college of midwives have taken this course of action."

But the Employers and Manufacturer's Association said New Zealand's pay equity issues are not unique.

Spokesperson Kim Campbell said the issue is political and should be dealt with in parliament.

However, he said there is no definitive answer to the issue, as he's not aware of any legislation in the world that has solved the issue satisfactorily.