Before the summer camp scandal and the latest claims, Labour was warned it had a major problem.

The Labour Council was told two years ago that there was a troubling culture of bullying, sexual harassment within the party.

A witness to the latest Labour sexual harassment investigation told the council in a late-2017 written submission that instances of sexual assault happened in the party and reporting the behaviour was extremely difficult.

The witness, a 21-year-old woman, is also a Labour Party member. The submission came before the Labour summer camp scandal.

The allegations made against a member of the Labour leadership office by several members of the party led to President Nigel Haworth resigning over his handling of the issue and serious questions being asked of Ardern and those close to her.

The written submission came in the wake of the Harvey Weinstein scandal in the United States and made direct reference to that.

While there was obviously no way Labour could have known what was to come, the witness said the party was warned about its culture, and should have seen the summer camp incident as proof of the need to act.

"They could have said, we're going to deal with the wider problem we know we have, because here is a specific instance that proves it."

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The woman, who Stuff has agreed not to name, sent the submission to then-General Secretary Andrew Kirton, Haworth and Assistant General Secretary Dianna Lacy.

The submission itself describes "a troubling culture of bullying, and of sexual harassment and assault" within the Labour Party.

"Instances of sexual harassment, and of sexual assault, happen in our party. They don't often come to light, usually because the survivor leaves the party, but also because those survivors who stay have no official means of reporting such behaviour.

"This allows abusers to continue in the party.

"Having an unpublicised, intimidating process for reporting sexual assault and harassment in our party is costing us talented members. I believe our party needs to take steps to combat this culture, and to allow a mechanism for survivors of abuse and assault to come forward."

Stuff understands the submission was tabled at the Labour Council in November 2017.

Stuff understands it was then passed to a smaller group of high-level members of the Labour Council.

When contacted by Stuff, a member of that group, Amanda Hill, said she did not work on the issue in the months between November and the next council meeting in February.

She said she could not recall what had been said at the February meeting, or whether the submission was discussed.

The submission's author was later asked to give evidence to a three-person panel about her experiences with the man accused of harassing up to 12 people. The man worked for Parliamentary Service in the office of the Labour leader.

She does not claim to have been sexually harassed by the individual.