Eleven prisoners serving life sentences were released after a Parole Board review last year - more than a doubling of the number five years ago.
In its latest annual report for 2018 which reveals the figures, John Costello, chairman of the board, criticises for the second year in a row an "unacceptable" backlog in getting reports from prison governors, the gardaí and psychiatrists.
There were 348 life sentence prisoners in custody at the start of this year, according to the report. The vast majority of lifers are convicted murderers.
The average sentence served of a released lifer last year was 17.5 years, down from 18 years the previous year.
Figures show an increasing number of lifers being released over the past five years, steadily increasing from four in 2014, up every year to 11 last year.
Mr Costello said lifers are only released when they have reached “metanoia” - a Greek word meaning “a change of heart and mind” - after years of often unrecognised help by psychologists, addiction counsellors, probation officers, teachers and other prison staff.
Once freed, lifers are under licence for the rest of their lives and can be returned to prison if recommended during annual reviews by the Probation Service. Two released prisoners were returned to custody last year: one at his own request over “possible public safety concerns”; and the other following a charge of assault.
In his annual report, Mr Costello also blames a lack of proper resources in Irish prisons for delays in inmates being considered for release.
The report shows 63 case were referred to The Parole Board, which reviews prisoners’ cases and recommends their release or continued detention, last year.
But more than four times that figure, 280, were carried over from the previous year. Figures in the annual report for the last five years show on average 280 cases are carried over every year.
‘Not acceptable’
Mr Costello said many of these delays arise because “the Parole Board is waiting for reports from psychology, probation and other services.”
“It may not be possible to adhere to acceptable timelines when a review cannot occur until all necessary reports are received,” he said.
One of the main reasons for delays appears to be a lack of proper resources in the prisons and across the various services.
Mr Costello said the Parole Board sends out a “monthly reminder” to some of the authorities and services about delayed reports, and “when deemed necessary, individual requests for outstanding reports are issued.”
"There can be additional delays waiting for reports from prison governors, An Garda Síochána and the Prison Review Committee," he added.
“When independent psychiatric reports are requested this adds to the time required to conclude the review process.
“As I stated in our annual report last year, these delays are not acceptable.”
The mental health of prisoners remains “a major concern of mine”, added Mr Costello, who has highlighted the same issue in previous reports.
“Another major concern of the Board is the serious abuse of drugs and alcohol by many prisoners,” he said.
“A huge number of life sentence prisoners commenced taking drugs and/or alcohol as young teenagers. Figures provided by the Probation Service detail that 89 per cent of offenders under the supervision of the Probation Service have had or currently have an addiction to alcohol and/or drugs.”