Labour Party President Nigel Haworth's resignation Wednesday comes after a 19-year-old party volunteer told online site The Spinoff that last year she was pinned down and violently sexually assaulted by a party staffer.
A barrister, Maria Dew, has been appointed to review the Labour Party's handling of the case and is due to report directly to Ardern next month.
The Prime Minister said she's waiting on an independent QC report to decide what to do, but has maintained that when she was first told about the allegations she specifically asked if they were sexual or physical and was told they were not.
But added: "Ultimately this is Jacinda Ardern's employee [the alleged offender], it's not Nigel Haworth's, and she's ducking and diving on that accountability".
Ardern discussed the correspondence with Haworth, and while he stood by his statements on the issue - including that "none of the complaints the party investigated related to sexual assault" - she believed mistakes had been made during the process. She said inaction by senior party figures had left her feeling "angry, quite fearful and desperate".
When asked specifically if he thought Mr Ardern was a liar, Mr Bridges said it was possible, but "very unlikely" she didn't know the truth about the allegations.
Ardern said an appeal process led by a QC, established in August after Newshub revealed dissatisfaction with the party's original investigation into the allegations, was meant to resolve the matter and provide the Prime Minister with assurances that appropriate victim support and advocacy services had been put in place for the complainants. "I'm obviously incredibly frustrated, disappointed and concerned about this situation and the competing advice I have received", she said.
The Prime Minister is being urged to show leadership over a deepening sexual assault saga.
On Wednesday, Ardern said: "On behalf of the Labour party I apologise to the complainants for the way this matter has been dealt with".
The alleged victim told The Spinoff that she had raised her allegations of sexual assault during an internal inquiry, both verbally and in writing.
But Labour's Stuart Nash says Ardern will get to the bottom of this, because it cuts to the heart of what it means to be in the party. "I will take steps to make that offer available to them if they wish to take it up".
The complainants have not detailed their allegations to the police.