The College of Midwives says it has been left no choice but to take High Court action against the Government over pay discrimination.
The college which has more than 3000 members says this is a gender issue of pay parity discrimination and it will be filing its case under the Bill of Rights Act in Wellington's High Court.
Chief Executive Karen Guilliland said Lead Maternity Carers work with 90 percent of women having babies.
She said these midwives were paid the same as unskilled, or junior staff for a job which has them on call 24 hours a day.
Ms Guilliland said there was a real risk New Zealand would lose its world class maternity reputation if a financially sustainable payment system for midwives could not be agreed.
The Midwifery Representation and Advisory Services union, which represents midwives, says the action is courageous and necessary.
The union's chairperson, Linda Trillo said lead maternity carers looked after women for nine months and the job should be recognised as highly skilled.
"There's diagnostic, there's testing, there's screening, there's being on-call, labour and birth care, then there's continuity through the post-partum period, there's referrals, it's a very, very complex comprehensive job."
Ms Trillo said the action was about midwives being valued for their huge contribution to society and challenged the notion that women should accept less.