Those statistics, when you see them, generally knock you off your seat but it is a matter of whether we are comparing apples with apples," he said.
"Generally there is parity when you have women and males in the same roles. It is just that we don't have the same numbers of women occupying senior roles and men predominantly dominate those roles."
Mr Walsh said there had been a push in many workplaces to hire women but he believed hiring on the basis of gender was unfair.
"A lot of employers are trying to fix the gender balance in the office but then you have to look at the applicants when they come through the door.
"With any employment, the best person for the job should get the role. An employer shouldn't be focused on trying to employ a female for a role because they want to even up gender balances in the workplace."
The national median weekly income, $767 for men and $464 for women, displayed a gender-related imbalance in all regions.
Union organiser Shanna Reeder of Unite said a variety of factors still fuelled the gender-related wage gap in New Zealand.
Ms Reeder said women usually wouldn't put their hands up for higher paying roles as often as men, and often took time off work for maternity leave.
"It's strange because it's something that seems so clear; men and women should be paid equally. But when you look at statistics, you see how significant the gap is," she said. additional reporting by Cloe Willetts