Overcrowding, drug use and poor management of prison officers' time have led to a "tinder box" situation in Irish jails where criminals band together in gangs and violence is commonplace, according to the Prison Officers Association.
The association says within the last two weeks three officers were injured in Mountjoy Prison in Dublin, one sustaining a broken nose, one suffering a severe shoulder injury and a third receiving slash injuries to his chest and face.
The association described as "savage" another attack on a young prison officer in Wheatfield Prison which left the officer hospitalised.
Speaking at the association's annual conference in Kilkenny this morning, deputy general secretary Jim Mitchell said violence in prisons was increasing as a result of overcrowding, with stabbings and assaults a regular feature.
He said an additional problem was the failure of local management in prisons to adequately manage officers' time.
He instanced a recent outbreak of TB in Cloverhill Prison in Dublin, in which five prisoners had to be hospitalised, with consequent medical tests on other prisoners and prison officers, which placed further stress on officer man hours.
When a prisoner is brought to hospital there is a requirement for a minimum of two officers to accompany them and to be on hand at all times. Where the prisoner has demonstrated a tendency to be violent or to abscond, the number of officers required can increase substantially.
Mr Mitchell said a recent report had found three Irish prisons; Mountjoy, Limerick and St Patrick's were unsafe for prisoners and staff.
But he said better management of prison officers' time and a reward system for prisoners would help the situation. Allowing prisoners to earn rewards such as television in their cell and the right to wear their own clothes could go a long way towards encouraging good behaviour, he said.
Prisoners arriving in jail are currently entitled to wear their own clothes if they have three changes of clothes with them and are allowed to have a television in their cell. Where prisoners were behaving and earning rewards there would be less need for high numbers of officers to be on the landings, he said.
The association said violence in prisons was linked to the problems of overcrowding and the increasing influence of gangland criminals within the jail system.