The gender pay gap means from tomorrow women are effectively working for no pay till the end of the year, the Council of Trade Unions has calculated.
It said the pay imbalance between men and women on the average wage is 11.9 percent, and since this is 11.9 percent of the calendar year left, women are in effect working for free from now on.
The CTU's vice-president Rachel Mackintosh said it's possible and essential that everyone can be paid fairly, regardless of gender.
"There's been some really heartening developments in the last few years. There are equal pay claims, there are big differences being made for women but you can see from the [pay] gap that we're not there yet.
"We need the government to pass the Equal Pay Amendment Bill and help make the gender pay imbalance in New Zealand a thing for the history books."
Ms Mackintosh said pay inequality is even worse for Māori and Pasifika, with Māori women effectively working for free from 12 October (due to a 22.1 percent pay gap) and Pasifika women may as well have been working for free from 29 September (due to a 25.5 percent).
Stats NZ prefers to compare the difference in the median hourly earnings between genders, rather than than the average. They say it can reduce the effects of very high or very low earners that are exceptions to the pattern.
Their latest figures, from August, show the gender pay gap at 9.3 per cent - unchanged since 2017.
"While it has remained flat since 2017, the gender pay gap has been trending down since the series began in 1998, when it was 16.2 percent," their labour market statistics manager Scott Ussher said.
Ms Mackintosh said either way, the unfair gap between pay received by men and women is taking too long to be addressed.
"If the gender pay gap continues to close at the same rate it has since 1998 it will be 100 years until women are on average paid the same as men. It will take 36 years (to 2055)," she said.
Mothers also get a raw deal - a government report from 2017 has shown they are paid 17 percent less than fathers.
Slow progress closing the pay gap is not the only imbalance in conditions that needs work, said Zoe Brownlie, YWCA Auckland workplace programme lead.
"Through our work ... we know that initiatives such as non-gendered parental leave, flexible and remote working and a structured talent pipeline for women are critical to address not only the pay gap, but also increasing the number of women in [executive management] and governance roles" she said.
Ms Brownlie said the stories gathered through their annual Equal Pay Awards show there are many benefits to organisations and staff who do address the pay gap.
"What we have found is that an organisation looks under the hood at their pay practices and it starts a chain reaction identifying other opportunities for improvement.
"Previous finalists and winners have told us that being acknowledged as an equal pay champion has made them more attractive to top talent looking for forward thinking organisations and has also enhanced their workplace culture" she said.