UPDATED 3.23PM The Government has pledged to reveal what it calls the "dirty little secret" of sexual violence in New Zealand.

Social Development Minister Anne Tolley has pledged $46 million from this year's Budget towards sexual violence over the next four years - $40 million is new and $6 million is reallocated.

LISTEN ABOVE: Dr Kim McGregor QSO talks to Larry Williams

It will mostly go towards providing better victim support and prevention of sexual violence, and helping victims to reach out to those services, like the HELP charity in Auckland.

Ms Tolley said the services have been fragmented until now, and they know that's not good enough.

"It's not a national set of services that people can access wherever they are in the country, but the announcement today is about putting that right."

Interim funding of around $10 million was given to the sector in 2014.

Ms Tolley said it was to keep services open while more work was done to determine what was needed and what the costs would be.

"We've just got to better support them. So the funding will make a big difference because often they're often hand-to-mouth and year-to-year funding."

Green MP Jan Logie said it's a much needed boost for a sector that's struggled with under-funding and a lack of commitment from successive governments.

"More funding is an important first step and I know it will be an enormous relief to those battling to keep their crucial services available for the people in their community."

Clinical psychologist Kathryn McPhillips of support agency HELP said services like theirs have felt sidelined, as all the funding in the past has skipped over them, and in doing so skipped those who need it most.

She said the government's pre-budget pledge will help them make a difference for survivors of sexual violence.

"Now we're kind of standing together now everyone can talk about sexual violence so I think that that will have an impact. Rates of reporting will go up in response to this."

MP Alfred Ngaro said they've been advocating for this since 2004 so it's good to finally have the issue acknowledged.

"When we opened up for the enquiry we had 997 written submissions. We heard 87 submissions. We went right throughout the country and different hui both in the rural and the urban sectors."

The Government's chief victims advisor is welcoming the announcement.

Dr Kim McGregor QSO said we need champions in Cabinet, who are putting sexual violence into the Government's work programme as a mainstream service.

"About one in three to one in five females are affected by sexual violence, and one in about six to ten males, so it's a huge slice of the population."

However, major funding announcements for anti-family violence initiatives looks set to feature in next year's Budget, not next week's.

Anne Tolley said there is an overlap between the government's work on sexual and family violence, with the former about 12 months ahead.

"That's why we see it in this Budget, whereas the family violence we probably won't see until next Budget."