The Inspector of Prisons has warned that unacceptable overcrowding is the single greatest problem confronting the State's largest women's prison.

Judge Michael Reilly has also published figures showing that 86% of female committals to prison are for less than three months.

He has identified homelessness as a huge problem among inmates, saying no woman on release from prison should be homeless.

The Dóchas Centre on the Mountjoy campus in Dublin has consistently been overcrowded, according to Judge Reilly's interim report on the facility.

It found that six months ago almost three prisoners were crammed into every two places available.

The report says this increases tension to a level where the slightest thing could spark a major altercation.

The Dóchas Centre was divided into seven houses when it opened in 1999, with one house used as a "step-down" facility for women nearing the end of their sentences.

However, due to overcrowding, this house - part of which is used as a mother and baby unit - is now used for normal prison accommodation.

The maximum number of women that should be accommodated in the Centre should not exceed 105, with 24 places available for women prisoners in Limerick prison.

The report found, however, that the centre has "consistently operated way in excess" of its maximum capacity.

It said that on 8 July 2010 there were 150 prisoners in the centre when its maximum should have been 85. On 19 June this year, there were 141 prisoners there when the maximum should have been 105.

Judge Reilly said that between 2005 and last year, the annual number of committals to Dóchas and the smaller Limerick Women's Prison increased five-fold and that now 86% are for three months or less.

Almost half of committals to prison are for road and traffic offences.

He said the answer is not solely to build more accommodation and that the questions of homelessness and the lack of diversionary options for certain women in conflict with the criminal justice system should excite debate in civil society.

He also said homelessness is a huge issue and warns the State that it has an obligation to ensure that all women on release from prison have adequate, suitable and permanent accommodation and all relevant supports.