The Prison Officers' Association has voted to recommend to its members a rejection of the public sector pay and reform agreement.
Delegates at the association's annual conference in Killarney, this afternoon voted against accepting the agreement by 103 votes to 17.
During a four-hour heated debate, many of the delegates said they did not trust the Government.
POA President Jim Mitchell said: 'We will be organising a national ballot of our members on this important issue in the coming weeks.
'As decided today we will not be recommending acceptance of the agreement.'
Meanwhile, the POA says the number of inmates joining criminal gangs in prison is increasing and that prisoners are joining the gangs for their own protection.
It also heard that gangs are fighting for control of the drugs trade in prison.
Mr Mitchell says that while the gangs get bigger, the number of prison officers who are charged with controlling inmates is getting smaller.
Mr Mitchell also says there is now an urgent need for a place to put gangland criminals and a prison regime that is robust enough to protect those who have to deal with them.
Overcrowding on the agenda
The Association is accusing the Irish Prison Service of operating Ireland's prisons at 10% above capacity.
Overcrowding is still the main issue impacting on the country's prisons, according to the Association, and there appears to be little will to deal with it.
Mr Mitchell says overcrowding would not now be such a serious problem if the Government had not closed three prisons.
He says the smoke and mirrors policy allows the IPS to claim that an institution is 3% under capacity when in fact it is 7% over capacity.
