Labour says the government should be ashamed of its failure to address the gender pay gap for public service workers.
Male public service workers get paid up to 39 percent more than female workers on average, according to State Services Commission data released for the first time.
Yesterday, the SSC revealed eight years' worth of data showing the annual gender pay gap at 29 government departments.
Labour's Associate Workplace Relations spokeswoman Sue Moroney says the figures underline years of inaction by National to address the pay gap.
National scrapped the Labour Department's Pay and Employment Equity Unit in 2009, which had completed comprehensive pay equity audits for all government departments, she said.
"The Ministry of Women's Affairs was given funding and responsibility for continuing that work, but successive National Ministers have, instead, left those audits and recommendations gathering dust."
Ms Moroney said she had questioned what action had been taken with the audits, but her questions were met with "blank stares" by Women's Affairs.
"National should be ashamed of its failure to address its own performance when it comes to the gender pay gap, which has widened on its watch," she said.
Topping the list with the biggest pay gap in 2015 is the Crown Law Office and the Ministry of Defence, where men were shown to earn, on average, 39 percent more than women.
Those departments are followed by CERA with a 29 percent gap, and the SSC, with a 27 percent gap.
The only department where women were paid more than men was the Ministry for Women.
The department with the smallest pay gap was Maori Development, on 1 percent.