A police investigation has been confirmed regarding allegations of sexual assault on four teenagers by a 20-year-old man at a Labour Party camp. 

Labour's general secretary, Andrew Kirton, admitted to media on Tuesday that there was "too much of a delay between that happening and action being taken." 

ACT Party leader David Seymour says Labour is neglecting the rights of young people. 

"We have a prime minister who says she wants to put the children at the centre of everything - they actually put the Labour Party's political interests ahead of the interests of victims," said Mr Seymour. "And, at a time when trying to encourage people to report sexual crimes, we find ourselves with the Labour Party actively discouraging young people from reporting them - and I think that's a disgrace." 

Fiona McNamara from the Sexual Abuse Prevention Network told Breakfast that sexual assaults go unreported because victims want to avoid reliving the experience by having to retell their stories. 

"A lot of people don't want to report their stories because they don't want to have to go through the process of having to re-tell that again and again. And we also know that conviction rates are really, really low in New Zealand and it's estimated that only 13% of that 7% will go through the court process and result in a guilty verdict. So for a lot of people they just don't see the point." 

Mr Seymour says this is an issue that Prime Minister Jacinda Ardern can't dodge. 

"Jacinda Ardern needs to come out and show leadership and take ownership. It's not good enough to be the prime minister and stand by while her own political party is doing the exact opposite of what she says people should be doing in public." 

The prime minister told media on Tuesday that the focus is being taken away from the young people at the centre of the assault. 

"Focusing on me, that's a political response, that's about risk management. That shouldn't have been the focus here. The focus should've been on these young people who were involved. That's much more important than me knowing, so I'm not particularly concerned about that - as soon as I knew though I wanted assurances we'd done everything we could."

The Labour Party says it's taking immediate steps to ensure a safe environment at all Young Labour events in future including summer camps.