The Labour Party is "deeply sorry" after allegations of sexual assault at a Young Labour Camp have emerged.
Prime Minister Jacinda Ardern promised to personally investigate after four 16-year-olds were allegedly sexually assaulted or harassed at the weekend camp in February.
Two young men and two young women were assaulted by a 20-year-old man at the camp in Waihi, Newsroom has been told.
The allegations are that the man put his hand down the pants of three of the four victims.
Newsroom was told the man was removed from the camp the next morning.
About a third of those at the camp were under the age of 18, but there was reportedly "a large variety of alcohol available on Saturday night", and the alleged perpetrator was intoxicated.
Labour's General Secretary Andrew Kirton says the Labour Party is "deeply sorry... It shouldn't have happened."
In a statement released on Monday evening, he said Young Labour apologised to the people involved.
"We are extremely disappointed that an incident like this happened at a Labour event and we are working to make sure those involved receive any support they need. We are deeply sorry for the distress that’s been caused. It shouldn't have happened."
He did not say whether police have been contacted.
Ms Ardern attended the event herself but left early in the evening.
At the Government's weekly post-Cabinet press conference, Ms Ardern was asked about the allegations.
She said she had just arrived back in the country and had not yet been informed of the events - that's despite Labour's head office being aware of the alleged assaults, according to the camp's organiser.
"I went to the opening of that summer camp. I attended at the very beginning. People had just arrived, so certainly none of that was apparent when I was there," Ms Ardern said.
"This is the first I've heard of any such allegations, but now I've heard I will happily investigate, because that is not the behaviour I would expect of any Labour function."
Ms Ardern assured journalists she'd be looking into the matter personally.
"Given I've just heard it now, I ask for the time to go and look into it personally."
Newsroom was told the victims have been contacted by one of the camp's organisers.
Statement from the Labour Party's General Secretary Andrew Kirton
The Labour Party is extremely disappointed that young people attending the Young Labour camp were exposed to highly inappropriate behaviour by an individual who was also at the event.
Young Labour has apologised to the young people involved.
We are extremely disappointed that an incident like this happened at a Labour event and we are working to make sure those involved receive any support they need. We are deeply sorry for the distress that’s been caused. It shouldn't have happened.
The Labour Party has initiated an external review of our policies and procedures including those involving alcohol. This review will involve our various sector groups, including Young Labour.
We want to ensure a situation like this is never repeated.
The morning after an evening in which we understand several young people had consumed alcohol, Young Labour was alerted to complaints in relation to the behaviour of a 20-year-old man.
The camp organisers contacted me in the days following the event and explained what they understood had happened, and the action they'd taken in response to it.
Those included having clear processes in place such as a dedicated welfare phone line and designated support people.
We have also offered further, professional support to those involved.
I have subsequently banned the perpetrator from any future Labour Party events.