Prime Minister Jacinda Ardern has revealed an investigation is underway into how a report into the Meka Whaitiri incident was leaked to the Herald.

The leak was "hugely disappointing" and Internal Affairs had decided to investigate how it occurred, Ardern said from New York this morning.

"I'm hugely disappointed to see that it has been leaked. We were going through a process to make sure that that was being dealt with appropriately, that we were protecting the employee involved in the situation.

"I'm advised by the DIA, that they themselves will be undertaking an investigation as to how the report came to be leaked."

The former staff member at the centre of the incident has not responded to messages seeking comment.

National says the entire incident involving Whaitiri and her former staff member has been very badly handled.

Today the Herald reported the contents of the draft report into the incident that cost Whaitiri her job as a minister. It says Whaitiri grabbed her press secretary and allegedly caused bruising to her upper right arm. Photos of bruises were produced to the inquiry.

The report's author, Wellington lawyer David Patten, declined to comment today on either the report's contents or the fact that it had been leaked.

Ardern said that they were "going through a process" to try to protect the employee at the centre of the investigation. She reiterated that there were still points in the report that Whaitiri had contested and others which she had not.

Asked if she was unimpressed with Whaitiri's alleged actions on the day, Ardern said "obviously the fact the fact that I have stood the minister down out of her role as a minister demonstrates that I was not satisfied with what I read in that report".

Asked if Whaitiri was an appropriate role model for Māori, Ardern said she still remained a Labour MP and was someone who had worked "incredibly hard" in the past.

"She is still a Labour MP and someone who has worked incredibly hard across her electorate but has admitted that she wanted to work on some of the issues that had been raised.

"We need to face up to the mistakes when we make them and that is what she is doing.

"She is working to rectify some of the issues that have arisen out of this incident."

Whaitiri could also not be reached for comment this morning.

National's deputy leader Paula Bennett said the matter had been mishandled.

"You've effectively got a young woman who was grabbed physically by a minister because that minister missed a chance to be in the background on TV," she said today.

"What they're more concerned about was redacting the report and how that would actually come out and less about someone who, it sounds to me, has been through a really hard time."

Bennett said Labour's Maōri caucus needed to have a hard look at what kind of standards they were setting with their continued support for Whaitiri.

"There is an unfortunate undercurrent of violence and domestic violence in Māoridom and the message they're sending is this is acceptable at some level.

"When they're having violence by their own minister to an employee they need to look at the message that they are sending publicly.

"If it was my own son or daughter who had been grabbed by a boss like this, I'd be very upset and I would be expecting more."

Bennett said Whaitiri's future in Parliament was a matter for Ardern.

"The Prime Minister has made her decision and yet again it was a half measure, so [Whaitiri] is able to stay on as the [Māori caucus] co-chair. She's able to stay in her seat and do that work and even been told there is a pathway back," Bennett said.

"Let's not forget the Prime Minister had seen this report and if anything had underplayed it."

Meanwhile, former Labour Cabinet minister John Tamihere today told the Herald it was clear there was "touching" involved but no evidence of the staffer being pulled or dragged outside.

"The extent of that touching is up in the air. The second issue is that there was no grabbing, pinching or pulling. It beggars belief where that bruising came from if that second finding is correct. The third finding is there was raised voices."

Tamihere, the Waipareira Trust chief executive, said he had 200 staff on his payroll and he would approach them in a similar way to Whaitiri.

"I got 200 people on the employment roll out here. I've gone up and got people's attention ... how most humans do it, you touch someone on their arm, between the shoulder and the elbow.

"Once you've got their attention, you say 'hey, can we have a quick conversation over here'. Then of course you can say, 'hey listen, fool why didn't you do it this way'. That's how I picture it happening. I don't see this woman as a thug."

As for how Ardern had handled the saga, Tamihere said the Prime Minister couldn't do any more than she had.

"This woman has been elected by the constituents of Ikaroa-Rawhiti ... I'll put your house and my house on it that she will be re-elected in 2020. No doubt. What happens in our communities is that we get the benefit of a discretion … pulled out of the building, really? That didn't happen."

Labour's Māori caucus has backed Whaitiri, with co-chair Willie Jackson saying previously that they had heard from Whaitiri and stood behind her. They had not seen the report so had no evidence on which to revisit that support. Jackson could not be reached for comment today.

A spokesman for Jackson said he had no comment because he had still not seen the report.

Labour MPs and members of the Māori caucus Tamati Coffey, Peeni Henare, Poto Williams and Kiri Allan all declined to comment today.

Leah Haines, the Prime Minister's press secretary who assisted Whaitiri's staffer in the aftermath of the incident, did not return messages for comment.

What the report said

The incident occurred because Whaitiri was unhappy at not having been alerted to a photo opportunity at a media standup with Prime Minister Jacinda Ardern during a lunch break at a function in Gisborne.

Other ministers were standing behind Ardern but Whaitiri wasn't because no one had told her it was happening.

There is no dispute that Whaitiri had words with her staffer for missing the event.

The staff member claims that Whaitiri came up behind her in the foyer of the building and grabbed her arm hard and took her outside when she saw Ardern having the standup.

But Whaitiri denies physically touching her staff member at any stage. There were no witnesses.

David Patten, the Wellington lawyer who conducted the inquiry for Ministerial Services, the employer of ministerial staff, found on the balance of probabilities that the staff member's version was the more likely explanation.

He found that Whaitiri did not pull or drag the press secretary outside from the foyer of the building where the meeting was taking place.

But he found it more probable that Whaitiri approached the staffer from behind and grabbed her by the arm and that Whaitiri spoke in a raised voice to the staffer.

In evidence to the inquiry, the staff member said Whaitiri had blamed her for missing the media standup with the Prime Minister.

"It was during ... the break so I'd gone out into the hallway, gone to the bathroom and I'd just gone out into the hallway into the vestibule for a bit of a breather and that's when she came over," the staff member said.

"She grabbed me by the arm and pulled me outside and said she needed to talk to me and when we were outside she raised her voice.

"I wouldn't say yelled but she did raise her voice to me and asked me if I knew what I was doing in my job and did I realise I'd missed a media opportunity and that that was embarrassing to her because it was her electorate."

The staffer originally told the inquiry that Whaitiri had pinched her arm but changed that to grabbed.

"It was hard and it scared the living daylights out of me," she said.

In other parts of her evidence, she said: "She was definitely angry, and was definitely mad that I had screwed up. It scared me a lot and I didn't want to return to that [work environment]."

Ardern sacked Whaitiri last Thursday, a day after seeing the final report, saying she had lost confidence in Whaitiri at this time, but did not rule out a return at some point.

Ardern said she would not release the report to protect the privacy of the staff member but the Herald is publishing some of the evidence outlined in a draft of the final report in the public interest.

Whaitiri remains the MP for the eastern Māori electorate of Ikaroa-Rawhiti and Labour's Māori MPs maintain support in her as co-leader of the Labour Māori caucus.

In Whaitiri's evidence to the inquiry, she said that when she saw the standup taking place she looked for the press secretary and saw her coming towards her. She did not grab her.

She asked her to go outside with her.

"All I wanted ... was to go outside so she could see the stand up and because there were so many people around the dining hall it was hard to have a conversation cos people were talking over lunch. I thought it would be best ... to talk outside where there were less people."

Once they were outside, Whaitiri pointed to Jacinda Ardern's standup and asked what was wrong with that picture they were looking at.

"I was pointing at the situation and asking very direct questions and then being really clear — 'this is your role.'"

Whaitiri said the press secretary was apologising, and Whaitiri said: "This is your job, this is what you are supposed to be watching out for".

The whole thing had taken about two minutes, Whaitiri said "because while I was doing that ... the standup was over."

The incident occurred on August 27 at the Ngati Porou summit attended by Ardern and several ministers — Kelvin Davis, Nanaia Mahuta, Carmel Sepuloni, Eugenie Sage and Whaitiri according to the ministerial media diary. Whaitiri was suspended by Ardern as a minister on August 30, while Ministerial Services, the employer of ministerial staff, conducted an inquiry.

The draft report also makes it clear that a member of the Prime Minister's staff, press secretary Leah Haines, was closely involved in events after the incident. Haines had accompanied Ardern to Gisborne, and had seen Whaitiri's press secretary after the standup had ended and they were all back inside.

"She looked traumatised," Haines told the inquiry. "She wasn't crying but she just looked stunned and upset so I was concerned about her."

They decided to talk about it when they got back to Wellington.

Haines met the staffer two days later in Haines' Beehive office and Ardern's chief of staff, Mike Munro attended part of it. Munro contacted Whaitiri that day as well.

The next day, August 30, Haines also attended a meeting with the general manager of ministerial and secretariat services, Morag Ingram, who took a photograph of the staff member's upper arm. The staffer also took a selfie of the arm.

Patten questioned the staff member about the bruises, why it took three days to see them and whether they could have been caused by something else such as a door handle.

She said it wasn't until she was at a meeting with ministerial services on August 30 that they asked if there were any marks and until then she hadn't thought to look.

Patten's finding in the draft report is: "The photographs taken by Morag Ingram on August 30 2018 of [the press secretary's] upper right arm showing a bruise on that arm ... are consistent, in my view, with someone being approached from behind and grabbed by a 
right-handed person".

The inquiry also questioned Haines about whether the press secretary had said anything to her in Gisborne straight after the incident about being grabbed and Haines did not recall her doing so.

But Patten did not find any such omission to be of great note.

"Nothing in my view turns on the fact that [the staff] failed to mention to Ms Haines at this point that she had been grabbed by the minister."

Haines had been extremely busy, the staff member had been upset and arrangements had been made to follow up the matter when they both got back to Wellington.