Helen Clark says the PM was let down by her party when she wasn't told about sexual assault allegations at a Young Labour camp.

Helen Clark says it's "unbelievable" that Jacinda Ardern was not told about sexual assault allegations at a Young Labour camp before they surfaced in the media.

"Jacinda was let down. She should have been told immediately, actually, then events would have taken a different course.

"And I cannot understand why she wasn't told. Unbelievable."

ROSA WOODS/STUFF Former prime minister Helen Clark, says the prime minister should have been told immediately about sexual assault allegations, then events would have taken a different course.

Labour general secretary Andrew Kirton has come under fire for not telling police, parents of the alleged victims, or the prime minister - his boss, about allegations a 20-year-old man sexually assaulted four teenagers at a Young Labour camp near Waihi in February.

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Over a text message, Kirton declined to comment, saying he had "nothing more to add to what I said at the time".

KEVIN STENT/STUFF Labour general secretary Andrew Kirton had nothing to say after former PM Helen Clark said it was 'unbelievable' that Jacinda Ardern was kept in the dark about sexual assault allegations.

At the time, Kirton said the Prime Minister was kept out of the loop because Kirton said the advice he received was that it could cause more damage to the victims if they were "under the impression or feeling or knowledge that a widening circle of people were being told".

He said he wouldn't change the way the party had handled the situation but in future would tell Ardern if that was what she wanted.

Asked if there should be ramifications for Andrew Kirton or those in party management, Clark said: "If you get out the book and ask what would Helen have done, well, draw your own conclusions."

"She's done her best to repair it after the event, but leaders never like to be blindsided."

In a statement, a spokesman from Ardern's office said: "As the Prime Minister has said, there are more serious issues here that concern her than whether she was given an early warning by the party."

Clark made the comments during a trip to Wellington this week to announce the results of a survey around youth smoking rates by independent organisation Action for Smokefree 2025 (Ash), for which she is patron.

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