The views of relatives of murder victims "are seriously considered" before the Parole Board reaches a decision to recommend a prisoner be released.
John Costello, chairman of the Parole Board – which advises the Government when long- serving prisoners should be released – said the board "quite often" receives letters from victims or their families before they review a specific prisoner.
"If the case involves a murder, many family members are still experiencing severe trauma and mental health problems many years after the death of their loved ones," said Mr Costello in his 2012 annual report.
"These letters are seriously considered by the board members before reaching a decision."
Mr Costello said that in the last year Justice Minister Alan Shatter had – on the recommendation of the board – agreed that certain life prisoners could be released on parole after about 13 years, subject to "appropriate conditions".
The average term served by a life prisoner is currently 17.5 years. The report, launched yesterday, comes ahead of an inaugural conference of the Parole Board to be held tomorrow.
The conference will discuss how new laws will place the board on a statutory footing.
At present, the final decision regarding the recommendations of the Parole Board lies with the Justice Minister, who can accept them in their entirety, in part, or reject them.
Last night, Mr Shatter said the board will be strengthened and its functions improved by being placed on a statutory footing.