Minister for Justice Dermot Ahern has said that around 550 new prison spaces will be opened by the end of the year.
He was speaking at the official opening of a new 52-cell block in Castlerea prison in Co Roscommon which can accommodate up to 100 prisoners.
The prison which is the committal prison for the West and North West also houses feuding criminal gang members from Dublin, Limerick and Sligo.
New blocks are also due to be opened in Portlaoise and Wheatfield Prisons.
These will accommodate approximately 200 prisoners each.
The refurbished Separation Unit in Mountjoy which will also provide an additional 50 spaces.
