Labour leader Jacinda Ardern says she cannot rule out other instances of sexual abuse at previous Young Labour events.
Speaking to media this afternoon, Ms Ardern said she was not aware of any previous instances at events she had attended as an MP and as a member of Young Labour.
"[However], I cannot, hand on heart, rule out that this hasn't happened before."
Ms Ardern said she would like to meet the sexual assault victims, but needed to now wait until police investigation was complete.
The Labour Party this afternoon announced a barrister will provide independent advice and support on how the party deals with sexual harassment and abuse in the party.
Ms Ardern and party president Nigel Haworth unveiled a number of key measures, two days after it emerged four 16-year-olds were sexually harassed or assaulted by a 20-year-old at a Young Labour camp.
Senior Barrister Maria Berryman has be brought in to look at how the party deals with harassment and abuse at other Labour party events.
Labour also confirmed today it had suspended all events held by its youth wing as it reviewed the sexual assault claims, one of which was now being investigated by police.
Mr Haworth said when they were reinstated they will be run by the party and not Young Labour officials. They will also be alcohol free and a senior member of the party will be present.
According to Newsroom, more than 50 people attended the Labour summer school camp and about a third were aged 18 or under.
On the camp's second night, a party was thrown.
Four people, all aged 16, were sexually harassed or assaulted by a 20-year-old. Three of them said the 20-year-old put his hand down their pants.
Labour Party general secretary Andrew Kirton told The AM Show this morning that he was aware one of the individuals had taken the matter to the police.
"They have our full support to do so," he said. "We wanted them to have a say and be in charge of what happened next."
This afternoon, party president Nigel Haworth said all Young Labour events would be suspended while an independent review, aided by the Sexual Abuse Prevention Network, takes place.
The review would look at the policies and procedures in relation to the party's events, including those held by Labour's sector groups.
There will also be ban on alcohol at any Labour events attended by anyone under 18.
"We need to take the time to properly review issues around how best to create the safest possible environment at all our events," Mr Haworth said.
Prime Minister Jacinda Ardern said she had been making her own inquiries to fully understand what had gone wrong at the camp.
"It has become very clear to me the extent of our failure to both provide a safe environment for those young people at the Waihi summer camp and to properly deal with serious concerns raised by several attendees in relation to sexual misconduct and alcohol."
Labour had failed the young people who told the party they had been hurt, Ms Ardern said.
"This failure left them feeling abandoned and I am deeply sorry for that. It's not good enough, we let them down."
Party general secretary Andrew Kirton would be contacting all attendees at the camp to apologise and offer support.
Mr Haworth said senior party officials put too heavy a responsibility on Young Labour leaders to deal with the aftermath of the incidents.
"I apologise for that," he said.
"We need to support them too."
Police investigation underway
Police said they had begun an investigation into the allegations made to them and that the first step would be to assess information available to them to determine what is required from an investigation perspective.
Detective Superintendent Chris Page would lead the investigation and police are encouraging anyone with information to come forward.
"Our priority is to ensure that anyone who wishes to speak with us can feel comfortable in doing so, and to ensure that appropriate support services are available."
There was alcohol at the party despite the victims' ages. Newsroom reported a "mountain" of alcohol including rum, vodka, cider and a large array of RTDs was being consumed by many people including a 15-year-old boy.
Prime Minister Jacinda Ardern yesterday told Morning Report it was her understanding there were consent forms, but they were more around their attendance.
Newsroom reported the camp's supervisor went to bed about 9pm and was not present at the party. There were also videos of drunken scenes and at least one man stripped to the waist dancing on a table.
The perpetrator was not a Young Labour member or staffer, according to Ms Ardern. He had not, as far as she knew, been offered counselling.
Police have offered to discuss the events with people who want to, without making any discussions public. They said anyone with relevant information should know that an official complaint does not need to be laid for investigations to begin.