An inmate was forced to sleep on the floor of a search area in Mountjoy after there were no more beds available.
Authorities have moved bunk beds into the basement areas of A, B, C and D wings as overcrowding problems persist in Ireland's largest prison.
An African inmate had to be housed in a search area on B-division after there was a severe bed shortage.
Minister for Justice Dermot Ahern recently admitted Irish prisons were full.
"On 15 November, 2010, there were 4,416 prisoners in custody as compared to a bed capacity of 4,430. This represents in effect an occupancy level of 100pc," he said.
The figures are not a true reflection of the complete prisoner population with 666 prisoners on temporary release.
Mr Ahern described the temporary release programme as "an important vehicle for re- integrating an offender into the community in a planned way".
"The Irish Prison Service has been engaged in an extensive programme of investment in prisons infrastructure which has involved both the modernisation of the existing estate, the provision of extra prison spaces, and the improvement of the prisons regime," he said.
"Since 1997, in excess of 1,930 new prison spaces have come on stream in the prison system."
"These include the new prisons in Castlerea, the Midlands, Cloverhill, the Dochas Centre and new accommodation in Limerick, Portlaoise, Castlerea, Mountjoy and Wheatfield prisons and at the open centres in Shelton Abbey and Loughan House."
Mountjoy has begun a €7m revamp in recent weeks to alleviate the problems.
The main aim of the project is the transformation of former dungeons to create 38 more spaces for convicts.
Work has begun on refurbishing C base, where the cells will have their own toilet facilities -- a luxury for prisoners housed in the new area, who are used to "slopping out".
An Irish Prison Service spokesperson said work should be completed in spring 2011.
The extra space will fall well short of solving the overcrowding problem at Mountjoy.
On August 1, 2006, when 21-year-old Gary Douch was kicked, beaten and strangled in a holding cell he shared with six others, the prison's population was 525.
When Derek Glennon was stabbed to death at the jail in June 2007, the population was 568 -- despite a commitment that it would not exceed 480.