More links between Deputy Police Commissioner Wally Haumaha and New Zealand First have emerged, prompting calls for NZ First MP Tracey Martin to step aside from leading the inquiry.
Mr Haumaha's appointment was questioned after it emerged he called the alleged police rape of Louise Nicholas "nonsense" during an investigation in 2004.
Mr Haumaha once stood to be a candidate for NZ First, and it's now come to light that he's whanau of one of the party's MPs - deputy leader Fletcher Tabuteau.
"Revelations that NZ First's Deputy Leader Fletcher Tabuteau is related to Mr Haumaha; that Mr Tabuteau's uncle and close friend of Winston Peters, Tommy Gear, is a senior leader of the marae chaired by Mr Haumaha; and that Mr Peters spoke at an event at the marae last year to celebrate Mr Haumaha's promotion to Assistant Police Commissioner make it untenable for Ms Martin as a NZ First MP to have anything to do with this inquiry," National Party spokesperson for police Chris Bishop said.
Prime Minister Jacinda Ardern says there's no conflict of interest having another NZ First MP running the inquiry.
"We run into conflicts of interest as Government on a regular basis," Ms Ardern said on Monday.
"It's for us to therefore manage that. I'm satisfied that we've been acting appropriately making sure that we respond to issues that have been raised in the appointment."
Ms Ardern did not condemn Mr Haumaha's comments that led to the review in the first place.
"The first step is the process... We are looking at the process, what information we should have had at the time that we made the decision and then we will move from there," Ms Ardern said.
The inquiry was due to start today - however the chair, Dr Pauline Kingi, resigned last week after it was revealed she had endorsed Mr Haumaha on LinkedIn.