Planned new "observation cells" for mentally-ill prisoners are likely to be just "a cleaner version of padded cells", the Irish Penal Reform Trust has warned.
Accusing the Minister for Justice, Mr McDowell, of effectively reneging on a commitment to eliminate padded cells, the trust said that proposed replacements would still fail to meet human rights standards.
The comments are contained in a report that calls for "radical restructuring" of the plans for observation cells, designed to replace padded cubicles, which were last year deemed "unacceptable" by Mr McDowell.
The author of the report, Dr Valerie Bresnihan, warned that the new facilities would "essentially remain places of solitary confinement and therefore places of psychological damage".
She added: "Despite the good intentions of many in the Prison Service, Ireland is again likely to fall short of accepted international standards. This is not acceptable."
Specifically, the report complains of "the absence of a medical ethos" in the plan for observation cells, and a lack of accessible services in both prisons and the community for those with mental illness.
It criticises "the over-drugging of mentally-ill prisoners returning from the Central Mental Hospital", and the shortage of appropriately qualified prison medical staff.
And it also condemns "a lack of official recognition that suicidal prisoners should never be placed in isolation of any sort".
Dr Bresnihan notes that the guidelines for the new cells have not yet been finalised, but says her findings are based on official information made available to her. She also acknowledges that some of the planned changes are positive.
These include the provision of fixed beds of normal height, call buttons, and toilets in or adjacent to every cell.
Inmates will also be given a "heavy green gown" instead of being naked, she adds, and walls will be "soft-surfaced so as to protect the prisoner from self-harm". Three different types of the new cell are being built at Cloverhill Prison, after which further consultation is to take place.
But Dr Bresnihan stresses the difference between "observation cells" - which she defines as being mainly used for disciplinary purposes - and "observation rooms", which form "only one aspect of an overall therapeutic strategy".
As her main recommendation, she urges that the planned cells be "converted into observation rooms: i.e., they must be underpinned by a medical ethos".