The chief inspector of criminal justice has said a parole board should be introduced in Northern Ireland to assess prisoners prior to release.
Kit Chivers told BBC NI's Nolan show current schemes did not give enough incentive to prisoners to change.
Under such schemes, inmates are freed after serving half of their sentence.
"In the case of serious, violent sexual offenders, we could do well to have a system which appraises them before they came out," Mr Chivers said.
"For these serious and violent offenders, we should look at them very carefully at the 50% stage of their sentence and think, 'Is this person really fit to go back into the community?'" he said.