A former Labour party volunteer says he directly raised allegations of sexual violence with party president Nigel Haworth.

Haworth issued a statement on Tuesday claiming a 19-year-old woman did not tell him she was sexually assaulted by a Labour staffer, when they met in August 2018. He also said the accusation was also not provided to a panel established to investigate the man's conduct.

Prime Minister Jacinda Ardern has repeatedly said she was not told the allegations were of a sexual nature. 

But one of the 12 complainants told Stuff he directly raised the matter with the investigating panel in March this year. 

He has provided Stuff with an email he sent to Haworth in May which refers directly to "this investigation ...which involved elements of predatory behaviour, sexual violence and physical violence."

And the man says he spoke about it in a two-hour meeting with Haworth in early July.

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Haworth has been approached for comment but has not replied.

"I definitely had those conversations with him and there is an email proving it," the complainant told Stuff.

"It's complete bollocks, rubbish. I don't know what is going on in his head...it is blatantly untrue that the party was not aware of any form of sexual violence or abuse."

The man was the only male complainant to the investigating panel. 

He says the staffer threw a punch at him and yelled a homophobic slur at him at a young Labour Christmas party in December 2018. 

The complainant is a professional in his early 20s, with a legal background. He quit his membership of the party because of the staffer's conduct. 

He was interviewed by the panel at Labour's Wellington headquarters on a Saturday in early March. He is "absolutely certain" he raised allegations of sexual assault, directly referenced the 19-year-old woman - who is a close friend of his - and another woman who he believed was assaulted but who had not made a complaint.

"I talked about him having sexually abusive relationships with the party, rape culture within the party generally with men.

"I tried really hard to put it in a context for them… I wanted them to understand.

"I said that there were elements and experiences of sexual assault by victims and I said to them it is not my responsibility to sit here and say to you [the woman] experienced X, this other victim experienced Y. 

"You need to take on board that I am telling you that this is something that is happening and you need to investigate this. I also told them about [the other woman]."

None of this was captured in handwritten notes from the panel interview later provided to him. 

In May, Haworth emailed the complainants to say the investigation was coming to a close. The man emailed back on May 21 to express disappointment in the "unacceptable" process.

He twice makes reference to "sexual violence" in the email and also wrote: "It is like the Party has learned nothing in the wake of the Young Labour summer school." 

In 2018, Labour was engulfed by allegations of sexual assault at a youth camp and had launched a review into how the episode was handled.

In June the party told complainants that there would be no disciplinary action against the man, who works in the Labour Leader's Office at Parliament, and is employed by Parliamentary Service, not the party.

Haworth offered to meet with the complainants, again at Labour's Wellington headquarters,  Fraser House, to air their grievances. 

The man says he had a two-hour meeting with Haworth, and assistant general secretary Dianna Lacy was present.

"It wasn't recorded and no notes were taken. The context of me talking about the sexual violence was: this exists, these individuals have experienced these things but I don't feel comfortable talking to you about the details of it because it is not my story to tell. 

"There was no question whatsoever that we were talking about sexual violence."

During the meeting he also raised concerns about the investigation.

"What happened at summer school created an opportunity for the party to be able to create a framework [for complaints] and they didn't. What I said to Nigel was… there was an opportunity to work with third party NGOs, like sexual abuse prevention network, to come up with a process that is solid.

"I said to him the process was wrong because it was like we were walking into a courtroom scenario, with the main person on the panel was a lawyer who ran it like a courtroom."

The man said he felt compelled to speak out about the man's behaviour.

"Abuse only happens in a vacuum, it thrives in silence. And that's the case here. For years he was able to bully and intimidate women and have relationships with women where he was abusive. 

"That was reasonably well known and yet he was still given opportunities within the party. Despite his reputation, he kept on going up the ladder."

The man says the complainants also felt vulnerable because the man had access to Labour Connect, a party database which contained volunteers' personal details including their addresses.

He is still anxious and feels "precarious and vulnerable."

"I feel like I am up against the entire establishment of Government. It is incredibly intimidating...we should never had gotten to this point.

"It is highly distressing watching your story being discussed at a press conference, at post cabinet. That is unreal."

On Monday, Stuff revealed the 19-year-old volunteer met with Haworth and Lacy at Wellington City Library to discuss the man's conduct.

She said she recounted the serious sexual assault and told them of incidents she was aware of involving other women.

"It was quite formal. I read out some bullet points about what I had heard had happened to other women and what had happened to me…

"Dianna spoke about the values of [leader Jacinda] Ardern and how things might be able to change culturally. Nigel said they took it very seriously and 'we do feel for you'."

She added: "I'd given them a series of names of other women and stuff I thought they needed to look into.

"They said they'd contact them."