The number of prisoners serving life sentences in the Republic's prisons has more than doubled to over 200 since the early 1990s, figures obtained by The Irish Times show.
Confirmation of the increased lifer numbers come as gardaí in Dublin and Cork investigate two weekend murders, the first gun killings of the year.
The increase in those serving life has come about following the increase in violent crime, notably the use of arms, which has led to the rise in murder rates in recent years.
Minister for Justice Michael McDowell and the Parole Board have also favoured a policy of prolonging life sentences to an average of around 15 years, up from the 10 to 12 years that life prisoners would have previously expected to serve.
The weekend killings follow a 46 per cent increase in the murder rate last year to 54 cases. Eighteen of these were gangland-style killings.
Figures released by the Irish Prison Service show the numbers serving life increased from 98 in 1998 to 198 in April of last year. The prison service said the current figure is around 205 life inmates.
The build-up of lifers in prisons, known as "silting", has become particularly acute in recent years, leading to calls from the Probation and Welfare Service for the establishment of a dedicated "lifer unit" within the prison system.
In the 60 months between July 1998 and July 2003, lifer numbers increased by 46 to 144. But in the following 21 months to April 2005, the number of lifers increased by a further 54 to 198.
As part of his desire to see life prisoners serving lengthy sentences, Mr McDowell last year instructed that books of evidence from murder trials should be made available to the Parole Board when life inmates become eligible for parole. He believes the board should be reminded of the detail of the crimes of life prisoners.
In the 1990s and early part of the current decade, a prisoner sentenced to life could expect to spend around 10 to 12 years in jail.
In the 1970s, many criminals sentenced to life served terms of between seven and eight years.
The Probation and Welfare Service's recommendation that a life-sentence unit be established forms part of a best-practice review of working with life-sentence prisoners.
It is proposed that staff at the unit would assess each lifer annually. Currently assessments are only carried out after seven years.
An enhanced liaison system is also recommended under which the families of prisoners would become more involved in their rehabilitation at pre- and post-release phases. Most of the prisoners serving life were jailed for murder.
Meanwhile, two people remained in Garda custody in Blanchardstown, Dublin, last night in relation to the murder of Dara McCormack at 9.30pm on Saturday. The 22-year-old was gunned down shortly after he left the family home at Whitestown Park, Blanchardstown.
He was shot by two men in a row over drug money. The dead man was hit once in the back by a shotgun blast. He had recently been the target of a knife attack. Gardaí are investigating whether the earlier incident is linked to his murder.
One of Mr McCormack's alleged attackers was being questioned last night. Gardaí are searching for another suspect. The second person in Garda custody is the partner of the man still being sought.
In Fermoy, Co Cork, detectives were last night investigating the murder of a 60-year-old man from the town. John Mahon, a self-employed painting contractor, was shot several times as he tried to flee from his attacker to his sister's house at St Bernard's Place at 12.30am yesterday morning.
Gardaí are following several lines of inquiry. Mr Mahon was seen having a row with another man in the town around 30 minutes before he was killed.
