Willie Jackson forced to revisit controversial RoastBusters comments

Cracks are showing in Labour, just hours after Willie Jackson announced he's joining their ranks.

The party's sexual violence spokeswoman, Poto Williams, is against the move, following Mr Jackson's controversial 2013 RoastBusters interview.

Mr Jackson was discussing the RoastBusters, a group who bragged online about having sex with underage girls, on his RadioLIVE show when he made statements many saw as victim-blaming and supportive of rape culture.

He described the group's online bragging about sexual encounters with drunk underage girls as "mischief" and asked a victim, "How free and easy are you kids these days?"

Shortly after Mr Jackson confirmed on Sunday that he was joining Labour as a list candidate, Ms Williams posted on Facebook, saying she was against the move.

"I was a vocal opponent of Mr Jackson's comments during the 'Roast-Busters' incident and I do not believe that his attitude towards victims of sexual abuse match what I expect of a member of the Labour Party. Especially a member of our caucus," she wrote.

"I appreciate that Mr Jackson may regret his comments, but I am yet to hear that he understands his attitudes and views are highly offensive to many New Zealanders. I'm yet to hear that he wishes to work on putting that right and apologise for his behaviour."

Speaking to media at Waitangi on Sunday afternoon, Mr Jackson told media that he apologised at the time and he's "happy to say sorry again for any hurt that interview caused".

"It was an interview and we were in the role of talkback hosts," he said.

"I'm not a perfect person, we make mistakes. We did an interview too casually and it went wrong."

Mr Jackson said his comments at the time were a consequence of his position in the media.

"Any talkback host's job is to provide two sides of the story and sometimes you get taken out of context."

He said running for Labour came with "a commitment to turn around the terrible stats in this area [of sexual violence]".