The Pay Equity Amendment Bill passed through all stages in Parliament, after being rushed through under urgency last week.
Workplace Relations and Safety Minister Brooke van Velden announced moves to raise the threshold for proving work has been historically undervalued to support a claim.
She said changes made in 2020 had created problems.
Ms van Velden said any current claims would be stopped and would need to restart under the new threshold, to show "genuine" gender discrimination and make sure the comparators were right.
Opponents of the controversial legislation have said it would make it harder for women in female-dominated industries to make a claim.
Judith Stanley, of Oamaru, said the group protesting outside the office of Waitaki MP Miles Anderson last Friday, were there to support the repeal of the Pay Equity Amendment Act
"There was no consultation ... It was a stitched-up deal before it hit the benches in Parliament," she said.
Annah Evington, of Oamaru, said the legislation was a "war on women" and would make it almost impossible for women to claim pay equity.
"They’ve thrown hundreds of thousands of women and men, lower paid men, under the bus.
"People have been working towards this for years and are now being told they’re back to square one."
She said essential workers were the most at risk.
Mr Anderson said it was "essentially not true" that the legislation changes would affect essential workers, and it was about the comparability of various occupations.
He alleged the opposition and unions were using this as a great opportunity to stir up a profile on the government, for themselves.
"The sky isn’t falling and people will still be able to take pay equity claims to court.
"It’s nothing to do with those on minimum wage, it is to do with comparison between occupations, and those discussions around gender-based discriminations in our workforce, they are still able to take claims to court," he said.
Mr Anderson said different systems, for nurses or for office administrators, revealed "real complexity" and past claims had dragged on in court for too long.
"It’s a direct comparison between occupations and the need to make sure equal pay is not being scrapped," he said.
The protest was organised by Roy Hill who said the group hoped to address their concerns with Mr Anderson.
Mr Anderson was in a conference in Rotorua at the time of the Waitaki protest, but said he was "always available" for consultation.
