Police Minister Stuart Nash is forced to defend the nature of his relationship with embattled deputy police commissioner Wally Haumaha, under intense questions in the House.

Police Minister Stuart Nash says he isn't mates with under-fire cop Wally Haumaha, but he admits referring to him in a jokey gym video.

Wally Haumaha was appointed deputy commissioner of police in late May by the Governor-General, after being recommended by the State Services Commission. Nash and Cabinet signed off on that decision.

That decision is now the subject of an inquiry after it emerged Haumaha had defended several police friends that Louise Nicholas accused of pack-raping her in the 1980s.

ROSS GIBLIN/STUFF Prime Minister responds to "drip-feed" of info about Wally Haumaha.

Now it has emerged that Nash had enough of a personal relationship with Haumaha to call him out in a jovial video he posted of himself working out in the gym.

The April 25 video, posted to Nash's Facebook page, is captioned: "Peeni Henare, Wally and Alf - just calling those out who doubted... all in the name of trying to keep the ageing body in some sort of shape. Hard work on a parliamentary diet :-)".

JARRED WILLIAMSON/STUFF Police Minister Stuart Nash says he isn't mates with Wally Haumaha.

At Question Time on Thursday, National's police spokesman Chris Bishop got Nash to confirm that the "Wally" Nash was referring to in the caption was in fact Haumaha.

When asked if he had a personal relationship with him, Nash said he did not lift weights with the senior police officer.

"Mr. Haumaha goes to the gym a lot, and every now and then we have meetings and joke about it," he said.

"Have I ever gone out for a beer with him? No."

Nash has maintained for weeks that he was not aware of Haumaha's comments about the Nicholas case.

The inquiry is focused on why exactly that information was not made available to the State Services Commission.

In a press release accompanying the initial appointment, Nash lauded Haumaha for his "clear vision and leadership skills."

"I'm very pleased to appoint Mr Haumaha to this role," Nash said.

"Wally Haumaha is a highly respected leader across our communities."

MARTIN DE RUYTER/Stuff Nash, centre, with Haumaha and other top cops.

But on Thursday he tried to clarify that it was not "his call".

"A panel by the State Services Commission were the ones who put forward the recommendation not me," Nash said.

He then took that recommendation to Cabinet for final sign off.

Prime Minister Jacinda Ardern was in Porirua, announcing a new mental health facility when she was informed of the apparent "matey" relationship between her police minister and Haumaha.

She said she was frustrated at these details being "drip fed" through the media.

She would not be drawn on whether she would be seeking a personal explanation from Nash.

Ardern would also not be drawn on whether she had been informed the pair may have been friends before the appointment of Haumaha.

She said she did not know how close they were, or whether their relationship could even be described as "friends".

Bishop said there was "big questions" for Nash about whether Haumaha still enjoyed his confidence as minister.

He stopped short of alleging that Nash had a conflict of interest however.

Earlier on Thursday the NZ Herald reported that three women left a joint justice project alleging bullying from Haumaha.