Pay equity advocates are calling for urgent action from the Government after the gender pay gap slipped back to 12 per cent for the first time since 2008.
The latest Labour Market income figures from Statistics NZ showed the pay gap had gone from an all-time low of 9.1 per cent in 2012 back up to 12 per cent in June this year.
The last time the gap was 12 per cent or more was in 2008.
Minister for Women Louise Upston said the increase was disappointing after a downward trend in the gap over the past 17 years.
Upston said it was employers who needed to act by assessing their own processes and ensuring there was no pay gap.
"Closing the gender pay gap requires making conscious, measured and reported efforts to tackle pay differences between men and women."
However, the Public Service Association's Assistant National Secretary Kerry Davies said the Government should step up.
"The Minister for Women says the equal pay issue needs 'conscious, measured and reported efforts. We agree, and we urge the government to walk the talk - by agreeing to fully implement the Joint Working Group's recommendations.
"If government officials, employers and unions can agree on a workable way to deliver equal pay, then Cabinet should not drag its feet."
That group of government, business and union representatives reported back to the Government on ways to achieve pay equity in May but it was yet to announce a response.
Its recommendations included allowing employees to make 'pay equity claims' where they believed workers were paid less because the workforce was predominantly female.
Green Party women's spokeswoman Jan Logie also said the Government should adopt the Working Group report.
Logie said underpaying traditional women's work was a major contributor to women getting paid less than men.
"We need those jobs, we can't just tell women to change jobs. We need to pay women fairly whatever job they do."
The Pay Equity Coalition spokesperson Angela McLeod said any pay difference because of gender was unacceptable.
"Measures by the Government that will make a difference and pay women fairly are overdue and urgent."
Upston said the State Services Commission was working to fix any gender pay gap issues in the public service and public sector organisations had to report on the pay gaps in their strategic plans.
"I encourage all employers to follow their lead."
The Government is still considering the Joint Working Group on Pay Equity.
It was prompted by the landmark court case taken against TerraNova by aged care worker Kristine Bartlett in which she successfully argued under the Equal Pay Act she was paid less than men with similar skills and experience would be paid in comparable sectors.
The court's finding is having significant ramifications across the aged care sector and opened the way to court challenges from other sectors which are predominantly women.
The Ministry of Health has entered mediation over a New Zealand College of Midwives pay parity discrimination case on the basis of gender under the Bill of Rights Act.
The College has argued midwives' pay and conditions have not kept pace with traditionally male-dominated professions carrying similar levels of education and responsibility.
The pay gap is assessed by Statistics NZ by measuring the difference in the median hourly earnings between women and men in both fulltime and part time jobs.
In June, the median hourly wage for women was $22 while men earned $25 an hour.
The gap in the average wage was even larger at 13.6 per cent with women on average earning $4.09c less an hour than men.