Fine Gael claims overcrowding at Cork Prison is leading to hundreds of inmates being freed before they complete their sentence.
The party says government figures show that 470 prisoners were freed from the facility last year before they had completed their sentences and before they were entitled to remission.
Fine Gael TD Jim O'Keefe is blaming the situation on the closure of Spike Island Prison by the Minister for Justice.
He says he has been told that inmates are freed early every time a prison van arrives with a new group of criminals.
However, the Department of Justice has rejected the claims, saying the early releases are part of "structured and planned sentence management".