Prime Minister Jacinda Ardern said there were no excuses for Labour's botched handling of complaints, including a sexual assault claim, against a former party staffer.
"We have a duty of care and we failed in it," Ardern told media at her post-Cabinet press conference this afternoon.
She said it could happen to any party, and it was her job to address those mistakes and help other institutes to do the same.
She said the held two conference calls with the Labour Party's NZ council over the weekend.
She said the complaints made to the party were serious and needed to be heard in a timely way. "That didn't happen."
The terms of reference for the review by Maria Dew QC had been finalised but would not be released at the request of the complainants.
Dew said she wanted to look at the substance of the complaints and not the Labour Party processes, Ardern said.
So the party's lawyer, who had looked into the party's process, would hand that work to a third party. That would go to all involved parties and asked for feedback.
The ex-staffer, who was employed by Parliamentary Service and worked in the Labour leader's office, quit his job last week but continues to say he has done nothing wrong.
His resignation followed that of Nigel Haworth, who stood down from the Labour Party's presidency after Ardern challenged him over his handling of the complainants and the harm that the party's process had caused them.
The Labour Party cleared the ex-staffer of wrongdoing in July, but Maria Dew QC is now reviewing the issue after complainants said the process was unfair and the sexual assault complaint was ignored.
National deputy leader Paula Bennett is calling for Ardern's and Grant Robertson's actions to be included in the terms of reference because a key issue was what they were told about the sexual assault complaint and how they responded.
"It's the only way it's going to clear the whole thing up, and it's about justice for the complainants."
But she had no faith that their actions will be scrutinised.
Robertson was reportedly told about the sexual assault claim at the end of June, but he has not commented on when he was told about such a claim, citing the QC process and the complainants' privacy.
He said last week that he had not been contacted by Dew, but would speak to her if asked to.
Ardern has said that a report in The Spinoff on Monday was the first time she had seen such a complaint from one of the complainants, suggesting that any previous complaint she was told about had been laid second- or third-hand.
She has said that the terms were being drawn up with the complainants, and their wishes should be paramount.
Ardern has remained tight-lipped about the terms of the ex-staffer's resignation, saying on Friday that she would not comment beyond saying she had received the resignation.
The ex-staffer's contract with employer Parliamentary Service would have included a "relationship breakdown" clause which, if invoked by Ardern, would usually have entitled him to three months' salary.
Bennett said that Ardern should come clean and say whether the ex-staffer was getting a payout.
Last week was a tumultuous one for the Labour Party, with Haworth and the complainants offering contradictory claims over whether a sexual assault complaint had been directly laid with the party.
Haworth said that neither he nor the party's panel investigating the complaints were aware of one, but several complainants disagreed and said that there was an email trail to support their claims.
Ardern has said that the Dew review, expected to report directly to Ardern in three weeks, would get to the bottom of it.