Calls have been made for urgent changes in the treatment of offenders with mental health problems following a report which shows high levels of intellectual disability among the prison population.
An unpublished government study shows that almost one-in-three tested prisoners have a learning disability or mild mental handicap.
The National Association for People with Intellectual Disability said the report highlighted the urgent need for people with intellectual disabilities to be placed in secure special facilities instead of prisons.
"We are dealing with people who might have the mental age of 12 or 13 years old. Our prisons aren't geared to dealing with these people and our prison officers aren't trained to deal with them," said Ms Deirdre Carroll from the association.
The Irish Penal Reform Trust called for the setting up of special mental health courts akin to the recently established drugs court.
"This would give the courts the option to cater more for mental illness and lack of supports," said Dr Valerie Bresnihan from the trust.
The Irish Prisons Service, which commissioned the study, said it doubted its findings that 28.8 per cent of prisoners scored below 70 in IQ tests. An average person has an IQ of around 100. The figures indicate that Ireland has a higher level of intellectually disabled prisoners than countries including America and Australia
A prisons service spokesman said it was believed that some 10 per cent of prisoners in Irish jails had such levels of intellectual disability.
"The report's finding is not in keeping with the evidence coming back to us from another health study and we are trying to iron out definitions," said the spokesman.
He said the service had been seeking clarifications about the report and no decision had been taken not to publish it or to bury it.
Amid calls for reforms yesterday, the Minister for Justice, Mr McDowell, indicated his willingness to publish the research, details of which were reported in the Irish Examiner.
Mr McDowell, who recently took over at the department, said he was not aware until yesterday of the report, commissioned two years ago.
"When I see the report I'll decide whether it should be published. But my inclination is to publish every report of substance," he told RTÉ radio yesterday.
Fine Gael's justice spokesman, Mr John Deasy, asked what steps the Minister would take to overhaul the prison service to deal properly with offenders with learning disabilities or mental handicap.
Ms Jan O'Sullivan, of the Labour Party, called on the Minister to publish the report in full and implement its recommendations.
"For those who have been charged and imprisoned there should be psychological assessment while in remand as well as supervised probation and sheltered training as an alternative to custodial sentences," she said.
"Where imprisonment occurs appropriate supervision, care and education must be provided to prisoners with intellectual disabilities."