A mother has told of how her intellectually disabled daughter was forced to go to the toilet in a bucket after being locked in a garage in a Sydney group home.

The case is one of a number uncovered during an ABC investigation into group homes, which has found reports of serious incidents of physical and sexual abuse in NSW and Victoria.

Jan Cox said staff locked her 25-year-old daughter Samantha in the garage for about two hours in September this year in an attempt to manage her behaviour.

It was the second incident at the Guildford home in just over a year. Samantha suffered extensive bruising when she was repeatedly kicked by a staff member in June 2012.

Ms Cox has spoken out about her experiences to draw attention to her concerns about inadequate staff numbers and training for support workers in group homes.

At another home in Menai in Sydney's south, parents allege their male sons were victims of physical assault and attempted sexual assault at the hands of a man inappropriately placed in emergency care.

In Victoria, one of the victims of group home worker Vinod Johnny Kumar, 31, who was jailed in November for 18 years for sexually abusing residents, has also spoken out about her experiences.

She wants to see changes in how group homes are run.

The focus on group homes comes as state governments continue to close down large scale residential homes in favour of group settings parallel to the rollout of the National Disability Insurance Scheme (NDIS).

The NSW Government has confirmed there will be a rise in demand for group homes as the NDIS rolls out between now and 2018.

It says it is working to meet the need for up to 25,000 more workers in the industry between now and then.

Safety and treatment of 'utmost priority'

Samantha Cox has a chromosomal condition called Smith-Magenis syndrome and has been in a group home since she was 12 because her behaviour is difficult to manage.

The bruised legs of Samantha Cox, who was abused while living in a group home in NSW. ( Supplied )

In June last year, Ms Cox discovered large bruises on her daughter's legs. Samantha said a staff member kicked her after she acted out.

Ms Cox reported the matter to the police but it never went to court because there were no witnesses.

The staff member lost her job, but Ms Cox wants to see more regulation of staff in the sector.

"This person can still be working in a non-government facility, perhaps working with vulnerable people in disability or aged care," she said.

The incident was followed by another in September this year when Sam was locked in the garage because she was misbehaving.

Ms Cox said staff failed to follow Samantha's behaviour management plan and put the home into lock down.

"Sam herself could have harmed herself in some way," she said.

"She had to use a bucket or something to go to the toilet in and found some paper to actually wipe herself. I think that's extremely degrading."

Ms Cox said communities would not accept children being locked in a garage, let alone a person with a disability.

"I trust these people to take care of my daughter," she said.

The mother of four wants to see more appropriate staffing, better training and more consistency of care in group homes.

"Sam has challenging behaviour so you don't put someone who hasn't been trained in that field or had experience in that field to manage her," she said.

She believes the problems are systemic.

"There are a lot of people in group homes who cannot articulate what may be happening to them."

A spokeswoman for the NSW Department of Families and Community Services said it could not comment on individual cases.

"The safety and treatment of people living in group homes is of the utmost priority for the NSW Government. All allegations are taken very seriously," she said.

"Should an incident or allegation occur, an investigation would follow so that appropriate action can be taken."

She said each group home resident has an individual plan which details their support needs, including identifying any behaviour issues.

"The mix and dynamic of a group home is important and takes into account residents' support needs and the services provided," she said.

"When additional support expertise is required, access is made available to a range of practitioners to provide targeted, person-centred services, including staff training and ongoing support."

Children 'physically abused' by resident

Ms Cox's experience is not unique.

The ABC has learned of another group home in Menai in Sydney's south where three parents allege their children were physically abused by a violent resident who had been placed in their group home for emergency accommodation.

The parents, who did not want to be identified, said the resident also tried to sexually assault their sons when the young men were alone with him.

They wrote to the NSW Minister for Disability Services, John Ajaka, and Opposition disability spokeswoman Barbara Perry about what they said was an inappropriate placement in the group home, which is run by a non-government organisation.

It is understood the man has since been moved to another home to live by himself.

The parents told the ABC they were happy with the response of the home and had also reported the matters to police.

They said more care needed to be taken with placements in homes.

Victim says assailant fooled everybody

Vinod Kumar was jailed last month for sexually abusing residents in a Yooralla group home in Victoria.

One of his victims, who has cerebral palsy, said she spoke out because she wanted to make sure no-one else went through an ordeal such as hers.

The 40-year-old said during Kumar's time at the home in 2011-12, he regularly suggested to her that the pair should have sex.

"I said: 'No thanks, no thanks. Not interested'," she said.

"But then when I needed to go [to the] toilet or bed or something, and I wasn't in my chair and couldn't do anything to defend myself, he would take advantage of that fact.

"[I] can't remember exactly because I'd take myself to another place."

The woman said she was angry when she discovered her housemates had been abused as well.

"It just makes me sick to know that I wasn't the only one affected," she said.

She said Kumar was cunning and fooled everybody.

"How one man, one person, can do this to so many innocent people, who are so vulnerable, including myself, and not realise, and flatly deny doing anything wrong, I'll never know." she said.

Parent converted to benefits of group homes

Antia Reidy was the biggest opponent of group homes when the NSW Government wanted to move her son Marty out of residential care.

Marty Reidy poses for a photo at Peat Island in the 1990s. He was a resident in the disability care facility on the island. ( Supplied )

She led the charge against the closure of the Peat Island large scale residential facility, which kept people with a disability contained on an island on the Hawkesbury River.

But the state government pushed ahead and three years on Ms Reidy is now a champion of group homes.

She says her son is able to work at a sheltered workshop and goes on regular outings.

Staff have also continued work that was started on Peat Island to get Marty talking and being social.

He is placed with friends from Peat Island and has his own space where he can care for himself.

"This model works well for Marty, and I think it has developed his understanding and tolerance of other people," Ms Reidy said.

"You always wonder how long a good thing can last."

Minister says group homes are working

The NSW Disability Services Minister said those families who had moved out of long-term accommodation were pleased with the transition.

"The regulation is very tight and is continually being monitored," Mr Ajaka said.

"There have been some incidences within the group homes but when you look at the overall number it is a small number."

He said independent reports were always sought and obtained and the appropriate action taken.

And he said a bill introduced to State Parliament in December would ensure more regulation.

"We also have other protocols in place, whether it's the ombudsman, the official visitors, who will all of course investigate and report to me," Mr Ajaka said.

Residents just want to be seen as individuals

The executive director of the NSW Council for Intellectual Disability, Aine Healy, said they heard mixed reports about group homes.

"Often people's complaints are about things they don't get choices about," she said.

"It's difficult for people to speak up or complain when things aren't right."

She said residents often just wanted staff who saw them as individual.

However, Ms Healy said it was important to have staff who understood the complexities of challenging behaviour and mental health.

A 2012 La Trobe University study published in international journals found there were problems with group homes.

It said the culture of some group homes meant residents were regarded as "other, childlike and not quite human".

"Routines and decisions were centred around staff needs rather than residents, and staff were focused on doing things for residents rather than with them," researchers noted.

A later study of group homes in Victoria by the same institution found it was not the model, but its implementation that was flawed.

For more watch 7.30 tonight on ABC 1.

Do you know more? investigations@abc.net.au