The chairman of the Parole Board has said the Minister for Justice agrees with a recommendation that prisoners serving life sentences could be released under certain circumstances after 13 years in prison.

John Costello said past statements by the board, and by various justice ministers, had indicated that life-sentenced prisoners should normally serve a minimum of 15 years.

Mr Costello said Alan Shatter had agreed with the board's recommendation during the last year that under certain conditions a prisoner could be released after 13 years.

"However, many life sentenced prisoners are not recommended for early parole because of, inter alia, the gravity and heinous nature of the offence and their risk of re-offending," Mr Costello said.

The Parole Board’s annual report said it convened on 12 occasions and reviewed 91 cases during 2012.

The number of interviews conducted by board members increased by almost 11% on 2011.

A total of 73 interviews were conducted during the year, which was the highest number since the establishment of the board.

All prisoners whose cases are being reviewed for the first time are interviewed by two members of the board.

The report noted that an interview was not always necessary for prisoners whose cases are being considered for a second or subsequent review, but the board will sometimes consider an interview to be in the prisoner's interests.

During 2012, 44 prisoners whose cases were being reviewed by the board for the first time were interviewed by members of the board.

A further 29 were interviewed as part of a second or subsequent review of their case.

Recommendations were sent to the minister in 91 of the cases reviewed, according to the report.

The recommendations in 57 cases were accepted in full by the minister and there were two recommendations that were not accepted.

Five cases were accepted conditionally or in part by the minister.

At the end of the year, there were 127 decisions still pending, according to the report.