An autistic and deaf Melbourne woman who helped murder her friend's housemate has avoided jail and will instead live in her family home under a court order, which has angered the victim's family.

But the Victorian Supreme Court found its only option besides prison was to allow 21-year-old intellectually challenged woman Georgia Fields to live in the community under a strict supervision order.

Deaf man, Robbie Wright, was pushed off a balcony in Ringwood in January 2015. ( Supplied. )

The two intellectually disabled men who helped murder 36-year-old Robbie Wright have been sent to a secure residential treatment facility, but there is no equivalent for women with intellectual disabilities or cognitive impairments.

Mr Wright's sister, Karen Wright, said she found it difficult to comprehend Fields was allowed to continue living at home with her parents.

"She gets to spend Christmas and birthdays like nothing happened," Ms Wright said.

"It makes me really frustrated and very angry that the non-custodial sentence has actually permitted her to do that."

Karen Wright and partner Ian are furious her brother's murderer will live at home under court order. ( ABC News )

Last year, a jury found Fields and two of her friends, Jake Fairest and Warwick Toohey, responsible for throwing Mr Wright over the balcony of his apartment in Ringwood, in Melbourne's outer-east, in 2015.

The trio faced a special hearing after the court found their disabilities or low IQs meant they could not follow a criminal trial.

As the trio was found to have committed the murder under the Mental Impairment and Unfitness to be Tried Act, they were not sentenced but were instead liable to supervision as ordered by the court.

It means the judge's key consideration in making a supervision order is treatment, not punishment.

Fairest, 27, and 30-year-old Toohey have both been committed to the Disability Forensic Assessment and Treatment Service.

Desperate need for secure treatment facility

Fields has been put on a non-custodial supervision order allowing her to live with her family under strict conditions which include a curfew, counselling and a requirement that she is supervised when leaving the house.

Justice Jane Dixon found the state's women's prison could not provide suitable support or therapy to Fields.

"Ultimately, the safety of the community and Ms Fields is better served by ensuring a regime of targeted treatment, supervision and monitoring," she said.

But Ms Wright said Fields' case highlighted a desperate need for the State Government to fund a secure treatment facility to cater for women with disabilities.

"If she breaks bail ... the judge has already determined that she's not suitable for jail, where does she go?"

A report published by the Victorian Law Reform Commission in 2014 identified a number of examples where a person required secure supervision and services but were placed on a non-custodial supervision order because this was the only alternative to prison.

The commission also found the lack of accommodation options had resulted in outcomes that were "inconsistent with community safety" and "caused harm and trauma" to vulnerable people.

Women stay in prison longer with nowhere to go

Colleen Pearce is Victoria's Public Advocate and the legal guardian for a 39-year-old autistic woman who is being held on remand on minor offences because there is no appropriate accommodation.

Victoria's Public Advocate, Colleen Pearce, says women with disabilities face discrimination from the justice system. ( ABC News: Michael Barnett )

Ms Pearce told the joint standing committee on the National Disability Insurance Scheme the woman is allowed out of her cell for just one hour a day.

"When she is returned to her locked cell she spends hours and hours just screaming, vocalising her distress," she said.

"If she had accommodation and supports, it is absolutely clear, she would be released."

Ms Pearce said if the State Government had acted on the Victorian Law Reform Commission's recommendations it would have helped solve what she describes as discrimination faced by women with a disability.

"It is very difficult for judges ... because they do have to weigh up whether or not a custodial sentence in prison is the most suitable option and more often than not we know that it isn't so what are the alternatives?" she said.

"For men they can go to a residential setting where the treatment path is very clear.

"In other cases, where women do not have supportive home environments to return to ... then more often than not they're going to reside in prison for a longer period of time, simply because there's no other options in the community."

A spokesperson for the Department of Health and Human Services, tasked with overseeing Fields treatment plan, said it was providing advice to the Department of Justice which is leading the response to the commission's recommendations.

Disability justice system poorly resourced

Chief counsel of Victoria Legal Aid and mental impairment crime specialist barrister Tim Marsh said Victoria had exceptional mental health facilities but funding other treatment options had fallen behind.

Autistic and deaf woman, Georgia Fields, has avoided prison time for murdering a Melbourne man. ( AAP: Tracey Nearmy )

"The situation for people who have intellectual disabilities or other cognitive impairments ... is nowhere near as well-resourced as the mental health sector.

"Particularly for women, the number of appropriate facilities for women ... are really quite slim."

Ms Wright has vowed to lobby the Victorian Government to fund a secure residential treatment facility for women with intellectual disabilities or cognitive impairments.

"The judge's decision was that if there is an alternative available to her sometime in the future that [Fields'] non-custodial sentence will be reviewed," she said.

"We need to find somewhere for her to go other than her family home."

A spokesman for Acting Mental Health Minister Jill Hennessy said the death of Mr Wright was a tragedy.

"The Minister for Mental Health has asked the Department of Health and Human Services to conduct a review of current forensic disability services to identify appropriate models of care and accommodation of people with a disability," she said.

"A review of the service is underway and will address how female offenders can be more appropriately managed."

