Mrs Robinson said midwives needed a highly skilled four-year degree and took complete responsibility for the lives of mothers and their babies while being on call 24 hours a day.
Midwives' fees were a flat rate set by Government no matter how much or how little experience that midwife had and the only way to increase their wage was to take on extra patients, she said.
Workloads were also growing as pregnant women sought care earlier and more screening programmes and administration were introduced.
"Look at male professions in a workforce like plumbers or even veterinarians and the kinds of dollars they are bringing in.
"The more clients we take on, the thinner we spread ourselves.
"We really need to be taking on fewer women because their cases are becoming more complex," she said.
Mrs Robinson said as prices went up, the midwife pay rate was becoming unsustainable. Midwives earned an average of $100,000 but of that, ended up taking home around $53,000.
"Close to half of a midwife's gross income is going on expenses. We are running a whole business from that $100,000. There is no prospect of earning more."
National Council of Women president Rae Duff said in the 120 years of the council's existence,it had always supported equal pay for work of equal value.
"New Zealand has always been considered as a leader in gender equality but we have slipped in the last few years.
"We've got to change our culture so that sexism is realised and people consider whether they do have equality in the workplace."
Mrs Duff said it was important midwives were paid fairly as these women were bringing new parents and role models into the world.
"It's not about the money, it's about valuing the job they do and making sure they are getting equal pay."
A spokesman from the Ministry of Health said a copy of the proceedings was only received yesterday and the ministry was considering it.
Fees for delivery of maternity services were increased in 2007, by 9.2 per cent and by 2.5 per cent in 2012.
Funding for the payment of claims under the Section 88 maternity services notice had increased to $146.8 million a year from July 1, 2015.
This was a net increase on the previous financial year of $2.1 million. An announcement on how this money would be allocated was expected in the near future, the spokesman said.
