New research shows 'pure sexism' is hugely responsible for the gender wage gap.
A group of researchers have looked at productivity to see just how much sexism is to blame for the difference in what men and women earn - and they found there was virtually no difference in productivity.
Lead researcher from Motu Economic and Public Policy Isabelle Sin said women and men are statistically indistinguishable in the productivity and value added to their workplace, but women are only paid $0.84 for every $1 men are paid.
"We looked directly at how the output of similar firms varies with the gender mix of the employees, and used this to infer the relative value male and female employees add to their firms."
"We're finding women are getting paid quite a lot less for doing work of the same value," she said on TVNZ1's Breakfast this morning.
Motu's study looked at half of the working population between 2001 and 2011.
"For both genders, productivity is higher for workers who have been at the firm for longer, but the wages of women with greater tenure are not commensurately higher. The gender wage-productivity gap does not go away once women have had the chance to demonstrate their worth to their employers," Ms Sin said.
Ms Sin said the first step in combating the wage-gap was to "acknowledge there's an issue".
The research found commonly-cited reasons for the wage gap, such as women choosing to working in low-paying industries and taking time off to look after children, "can't explain it".
"You still have a lot of people who are denying it's an issue. It can't just be explained away. It's not OK. Women are really being paid less to do the same," she said.
"To put it simply, our research suggests sexism is likely to be a major driver of the gender wage gap. What we’re going to do about it is another matter."