A mental health group is calling for women-only psychiatric wards in a bid to protect patients from assault, intimidation and harassment.

The Victorian Women and Mental Health Network is reporting a number of cases of patient harassment and sexual assault in state wards.

The network's Cheryl Sullivan has been documenting problems women have experienced in acute mental health units over the past year, and says too often it is accepted as part of life.

"Many of the women who are actually in the units have experienced previous sexual abuse and so they are already quite vulnerable and can be re-traumatised," Ms Sullivan.

The issue is close to the heart of Karen Field, whose daughter was put in a high dependency unit of a mental health ward in a Melbourne public hospital after attempting suicide 18 months ago.

Ms Field says her foster daughter was "punched in the face" by a male patient and sexually assaulted by another.

"He was removed or put in isolation and then came back out, was taken back out exactly into the same area with her, and he assaulted her again before he was moved out permanently and put in another area," Ms Field said.

Ms Field says her foster daughter was never asked if she wanted to press charges, and about a week later there was another assault.

"A male patient that she knew yelled out to her. She sort of went in there and she was sexually assaulted," Ms Field said.

"She finally managed to get away. She ran to her room, locked herself in the shower and was found lying on the shower floor in the foetal position.

"The first I heard about the incident was at 10 o'clock the next morning."

The young woman is now 28 and still relies on mental health care.

"I remember sitting in the car with her, going I have to take her back there, what the hell am I going to do?," Ms Field said.

"What am I going to do with this kid? It was terrorising for her, terrorising for me. It was probably one of the traumatic things I think I have ever had to kind of feel."

Victoria's Health Department says it has introduced women-only areas to mental health units and has also introduced staff training in gender sensitivity.

But Ms Sullivan says the improvements do not go far enough.

"You can have a woman's corridor but if there is a spare bed in that corridor and a man needs admission, then you can still have a man who will be brought into that corridor. There is nothing there to say no, this is a women-only area," she said.

The call for a rethink on mixed gender wards has the backing of a national group, the Mental Health Consumer and Carer Forum.

"To the best of my knowledge, all states and territories have mixed wards and [if] there are anecdotal examples of women being harassed then you certainly need to rethink how we design the wards," the group co-chair Isabell Collins said.

The Victorian Women and Mental Health Network will launch a paper on the issue at the Alfred Hospital in Melbourne today.