National MP Sam Uffindell asked to leave King's College after violent attack on younger boy

National MP Sam Uffindell has detailed the late-night violent beating of a younger boy that led to him being asked to leave King's College while he was a student.

Speaking to Newstalk ZB's Heather du Plessis-Allan, Uffindell confirmed the incident and said it was "one of the dumbest, stupidest things I have ever done".

He also wouldn't rule out standing down as MP.

Aged 16 as a Year 11 student at the exclusive Auckland boarding school, Uffindell and three others jumped on the then 13-year-old boy and began beating him with what was believed to be unscrewed wooden bed legs.

The incident reportedly occurred in 1999 on the last night of term inside one of the King's College boarding houses.

It was reported by Stuff that the now MP for Tauranga apologised to his victim 22 years after the attack and nine months before he revealed his political aspirations.

LISTEN: National MP Sam Uffindell talks to Newstalk ZB's Heather du Plessis-Allan

"It was one of the silliest, stupidest things I've ever done. I really regretted it, I do really regret it still," Uffindell told Newstalk ZB.

Police were not involved but he was asked to leave King's College, and finished his schooling at St Paul's Collegiate in Hamilton.

Uffindell said at the end of the school year students went into the third-form dorm and "raided them".

With the boy, he said he punched him a "bunch of times" in the arms and body.

He and the other boys were called into the school the next day and asked to leave, Uffindell said.

He said he was gutted about the incident, "had taken ownership of it" and had thought about it for years.

He said he had "no recollection" of using bed legs to beat the boy.

"I still am sorry for what happened, I wish it had not happened."

Sam Uffindell is the MP for Tauranga. Photo / NZME

When asked about the timing of the apology and whether it was linked to his political aspirations, Uffindell said it was "not what happened".

He had reached out "sincerely" to apologise.

It had bugged him for some time, Uffindell said.

"I have never done anything like this before ... I wanted to make amends."

He said he fully disclosed the details to the National Party and was asked to "walk through" the story with the party when being considered as a candidate.

Asked by du Plessis-Allan if he was considering leaving, Uffindell said he was "just trying to talk to you guys" and would come to Wellington and talk to the National team this week.

In an earlier statement, Uffindell confirmed he "punched a younger student in the arm and body multiple times" when he was Year 11 at King's College, but did not recall using a wooden bed leg during the assault.

"I've reflected on this incident multiple times over the 20 years since it occurred, and have no recollection of using anything other than my fists.

"Nevertheless, it's one of the stupidest things I've ever done and something I deeply regret.

"I've worked hard to be a better person than I was as a teenager and to be a good role model to my children."

National Party 'proactively informed'

A statement from the National Party said the party had been "proactively informed" about the incident by Uffindell during the selection process ahead of the Tauranga by-election.

"It was a significant event reflecting a serious error of judgment by a then 16-year-old for which he has apologised and regrets to this day," the statement read.

The victim, who was not named, told Stuff that Uffindell contacted him through a mutual acquaintance in July last year to apologise, which the victim eventually accepted.

"But then a few months later I sat down to watch the news on the couch with a beer and there he was, running for Parliament," the victim said. "I felt sick."

Uffindell had reportedly not mentioned his political intentions during the interaction.

"We had a long conversation and I was grateful that he accepted my apology. My apology was genuine then, and it is genuine now."

King's College headmaster Simon Lamb said in a statement: "The issue referred to in the Stuff article today was a matter which the College dealt with 22 years ago. Since that time, the College has not been involved in any follow-up activity with those involved, including the recent discussions reported in the article."

Lamb said the school does not wish to comment further on the article.

"We have confidence in our disciplinary and pastoral care processes and we are clear in our messaging to the whole community that it is every student's right to feel safe at school," he said.

At a post-Cabinet press conference this afternoon, Prime Minister Jacinda Arden said the conduct of candidates and MPs was an issue for the party involved.

Asked about any hypocrisy given Uffindell has been campaigning for stronger action on gang violence, Ardern said as leaders "we need to be accountable for our members' conduct".

"It is up to the National Party and [leader] Christopher Luxon how they conduct their own affairs."

Deputy Prime Minister Grant Robertson said violence and attacks on young people were matters everyone should be concerned about.