Labour Party President Nigel Haworth has resigned today over the handling of a sexual assault allegation levelled at a party staffer.
Labour leader Jacinda Ardern accepted his resignation after being provided correspondence from complainants written to the party several months ago.
"In the last 48 hours I have read incredibly distressing reports of an alleged sexual assault involving members of the Labour Party," Ms Ardern said in a statement.
"It confirms that the allegations made were extremely serious, that the process caused complainants additional distress, and that ultimately, in my view, the party was never equipped to appropriately deal with the issue.
"I discussed the correspondence with the Labour Party President this morning. Whilst he stands by the statements he has made on this matter, I believe mistakes were made," Ms Ardern said.
Mr Haworth released a statement saying the resignation was effective immediately.
"I've come to the conclusion that regardless of the outcome of the appeal process into complaints about a Party member, fresh leadership will be required to take forward any recommendations from that process.
"I have greatly enjoyed my time as President and will continue in my lifelong support of Labour and its principles."
Mr Haworth told media yesterday he would "consider" his position once a review of the matter had been completed by a QC, which was not expected to be completed for a few weeks.
Today, in the a statement announcing Mr Haworth's resignation, Ms Ardern made an apology to the complainants.
"Raising an allegation of sexual assault is an incredibly difficult thing to do; for additional distress to be caused through the way those allegations are handled is incredibly upsetting.
"On behalf of the Labour Party I apologise to the complainants for the way this matter has been dealt with."
"I want a justice system in New Zealand where people feel comfortable coming forward and are listened to, but I also need to ensure the Labour Party lives up to that expectation too." She also said she would meet with the complainants.
Earlier this year, Labour began investigating after seven people made complaints against a staffer. Three-months-later, the staffer was cleared.
In August, the Prime Minister ordered a review by a QC after complaints about the process.
Following an article this week in The Spinoff, in which claims surfaced from a woman who said she raised a sexual assault allegation with the investigation, the QC will now look at the whole investigation.
The Prime Minister maintained she was never told by the party or its president, Nigel Haworth, that any of the complaints were of a sexual nature.
A statement released by Mr Haworth yesterday said the "serious allegation of sexual assault ... was not provided to the president and acting general secretary at a meeting in the Wellington Central Library or subsequently to the Labour Party Investigation Panel".