Women medical specialists are paid 12.5 percent less per hour than their male colleagues, research commissioned by the senior doctors' union has found.
The Association of Salaried Medical Specialists wants district health boards to introduce gender pay audits to try and close the gap.
The union's deputy executive director, Angela Belich, said the findings of the research carried out by Motu Economic and Public Policy Research provide an evidence base for anecdotal reports from women members who believed they were being paid less, but had no easy way of proving it.
"[The association] will be asking each DHB to conduct a gender pay audit using mutually agreed methodology to eliminate this inequality," Ms Belich said.
"We would also like to discuss how to eliminate unconscious bias so that the future doesn't continue to perpetuate the inequalities of the past."
For specialists without children, there was a smaller gender wage gap of 9.2 percent.
That rose to 13.6 percent for those with one child and to 17.2 percent for those with two or more children.
The research also found that the gender wage gap increased with age and was higher for specialists who worked fewer hours each week in their district health board job - reaching 22.9 percent for those who worked 30 or fewer hours.
The union said it was now up to district health boards to address the issue and ensure that men and women who did the same work with the same experience were paid equally.