The number of men claiming to have been sexually assaulted is rising steeply as victims increasingly find the confidence to speak up.

And organisations working with male survivors say that while women make up the vast majority of sexual violence victims, many assaults on men still go unreported.

Police estimate that during the past five years the number of male victims of sex assault has jumped from about 480 to 710. The number of female victims has also increased, but by about one-third, compared with an increase of about 50 per cent for men.

Because police record offences rather than victims, they can only give estimates on victims but say there has been a marked increase in reported sexual assaults on men.

Detective Senior Sergeant Mike McCarthy said men were now more likely to report sexual assaults - recent and historical.

"Most victims do not report sexual assault because of fear, shame and beliefs they will be blamed."

It was never too late to report a sexual assault, and police had specialist staff to assist victims and their families, he said.

Male Survivors of Sexual Abuse Trust national manager Ken Clearwater said there had been a big change in attitudes toward men as victims of sexual violence, including among police.

"We have guys that two or three years ago would have been laughed out of the police station."

Clearwater said despite high-profile sex abuse making headlines recently, the problem was still greatly under-reported.

"We're really behind the eight-ball in terms of people understanding the extent of the damage. "

He said it was a lot safer than it used to be to report the crimes.

"We just need to say, hey, this does happen and it's all right to come forward and get help."

Clearwater said nearly half of the survivors he worked with had suffered abuse at the hands of women.

"It's a massive problem, we need to get more support for men - we're the only agency in the country that have been doing this work."

Sexual Abuse HELP Foundation general manager Helen Sullivan said the service still worked mostly with women but more men were seeking counselling.

"When I first started this role [10 years ago] I don't think there would have been any men reporting a recent sexual assault and that certainly has changed in recent years."

There was an increased awareness of men as victims of sexual violence, she said, and better processes for people who want to report sexual assault.

The select committee inquiry into the funding of specialist sexual violence social services has received nearly 1000 submissions, but a date is yet to be set for hearings.