Momentum is growing for gender pay gap reporting to be made compulsory, with research released to 1News showing reporting reduces gaps by 20 to 40%
It also sees more women hired and promoted within firms, and benefits women on lower incomes most.
It’s estimated a woman earning the median hourly wage of $26.37 could get between $12.80 and $35 a week more.
As of June 2021, the median man’s wage was $29, a difference of $2.63 an hour.
Australia, Canada, the UK and EU all report their pay gaps – some publicly – others to a government agency.
The Mind the Gap campaign says based on its review of evidence, public pay gap reporting is most likely to be effective in New Zealand. It says ethnic and gender pay gaps should be required to be reported by organisations with 50 or more employees.
The gender pay gap currently sits around 9% in New Zealand.
"Just think about what $35 a week means for the groceries, how many loaves of bread, how many choices you can make," said Jo Cribb of Mind the Gap coalition.
"This is just the impact of discrimination and pay choices in our organisations."
A poll commissioned by the Mind the Gap coalition found 58% thought large businesses should regularly share gaps publicly, and 68% of people thought big companies should make pay gaps known to job candidates.
About 50 companies voluntarily report the information here in New Zealand.
Professor Gail Pacheco, director of the NZ Work and Research Institute at Auckland University of Technology, said having information about pay was powerful for those considering roles at a business or organisation.
Mind the Gap says based on international research, pay gap reporting laws helps reduce the difference between men and women’s wages by up to 40%.
Some say pay gap reporting will just add to costs and compliance issues for businesses, something Cribb doesn’t buy.
"This is an investment in having workplaces that are fair and equal, our conversations with businesses show they want this as well."
It could also affect morale for those who discover they work somewhere with low pay.
"Some of the research has found that woman are more likely to leave and change jobs where they are in an organisation that has a gender pay gap," Pacheco said.
Mind the Gap wants the Government to introduce legislation urgently. A select committee is considering the issue.
Jan Tinetti Minister for Women said education was important.
"While it takes time to go down the legislative angle was well, that takes a lot more time, but we can have an instant awareness campaign."