Hundreds of inmates have been forced to double up in cells due to chronic overcrowding in the country's prisons, it emerged today.
New figures revealed there are 3,790 prisoners in the Republic, compared to a bed capacity of 3,611 - an occupancy level of 105%.
Fine Gael's Charlie Flanagan claimed overcrowding creates tension, fuels violence and hinders rehabilitation of inmates.
He also maintained gangland figures were free to walk the streets while fine defaulters are kept behind bars.
Mr Flanagan said the figures, released by Justice Minister Dermot Ahern in response to a written parliamentary question, show 13 out of 15 of the State's prisons are packed beyond capacity.
"This is not just a matter of prisoner comfort levels, as some might think. It is about having prisons that are safe and having prisons that are functioning," said Mr Flanagan.
"Part of the role of prison is to help rehabilitate inmates.
"Rehabilitation is not happening at present as almost half of offenders are back inside within four years of release."
The figures, calculated on March 9, showed the women's Dochas prison had 108 inmates for a bed capacity of 85 and Mountjoy had 633 prisoner for its capacity of 540.
"In my local prison, the Midlands Prison in Portlaoise, prisoners are sleeping on the floors of cells," Mr Flanagan added.
"This prison is way currently way beyond capacity with 498 inmates occupying space for 469. Both prisons in Limerick are overcrowded."
The country's maximum-security Portlaoise Prison and Loughan House, an open centre in Co Cavan, were the only two institutions not full.
Mr Ahern admitted inmates have been doubled up. In response to the Dáil question Mr Ahern said there was a 65% rise in numbers in custody over the last year due, in part, to greater resourcing of the gardaí, more stringent legislation, detection and prosecution of crimes.
"Given the serious pressure that the Irish Prison Service has been experiencing during the past 12-18 months, in 2008 it became necessary to introduce additional contingency accommodation through the doubling up of cells in Mountjoy, Wheatfield, Cloverhill, Midlands and Arbour Hill Prisons and in the Training Unit. This provided 180 temporary bed spaces," said Mr Ahern.
"As the pressure shows no sign of abating the Irish Prison Service recently decided to increase their capacities through the doubling up of further cells, thus creating 200 additional temporary bed spaces which will come on stream shortly.
"In 2008, 70 new prison spaces were introduced at Shelton Abbey and Loughan House Open Centres."
He added that building projects in Castlerea, Wheatfield and Portlaoise Prisons would be complete in the coming months, creating an additional 400 extra spaces which will temporarily alleviate the situation pending the construction of new prisons at Thornton Hall, Co Dublin and Kilworth, Co Cork.
Mr Flanagan maintained the Government has also refused to move on legislation that would allow fines defaulters to pay off their debts incrementally rather than being thrown into prison.
"It costs €90,000 per prisoner per year to keep these people in jail," added Mr Flanagan.
"We now have the crazy situation where a majority of gangland murderers are free to walk the streets while one third of the prison population is made up of fines defaulters.
"An expensive, revolving-door prison system is a complete waste of taxpayers' money and does nothing to reduce levels of crime in our country."