The Equal Before the Law report calls for the Commonwealth and each state and territory to introduce a "holistic, over-arching disability justice strategy" to make the system fairer.

It highlights how people with disabilities, especially women, are much more likely to be the victims of sexual and other violence.

At the same time, many offenders with disabilities have reduced control over their behaviour and poor communication with police, lawyers, judges and prison staff.

Disability Discrimination Commissioner Graeme Innes said he was concerned by figures showing that at least 20-30 people with disabilities are detained in jails because they were found unfit to plead.

"Denying people appropriate accommodation, and the support needed to return to the community, is nothing short of a breach of human rights," he said.

Orana Law Society president Andrew Boog said people with physical disabilities were well catered for but those with intellectual disabilities or mental illnesses were not.

"The main problem is that not many people are trained in both law and psychology or psychiatry in order to look after and understand those who have a disability," he said.

Mr Boog was particularly critical of the way mentally ill offenders were handled.

"For all kinds of spruious reasons we have turned our criminal justice system into a mental health system, without addressing mental health," he said.

"Our jails are not built for that sort of thing."

The Intellectual Disability Rights Service (IDRS) applauded the Equal Before the Law report but found no surprises within it.

"IDRS...sees injustice occur on a daily basis for its clients who have intellectual disability," executive officer, Janene Cootes said.

Ms Cootes said people with intellectual disability risked finding themselves in jail "for offences related to behaviours they have little or no control over".

The report noted with "grave concern" that Aboriginal and Torres Strait Islander people are 1.7 times as likely as non-Indigenous people to be living with a disability and much more likely to be incarcerated.

Aboriginal Legal Service NSW/ACT chief executive Phil Naden said he welcomed the report.

"The disability of a client is not always physical and sometimes it can very hard to infer it," he said.

"We've had some common cases where people are assumed to be affected by alcohol at a time when they are suffering the after effects or the first onset of stroke."