The Prison Officers' Association (POA) is to recommend the acceptance of the new prison pay deal to its members after a meeting of its national executive today.
A national ballot of the 3,200 prison officers will be held in the coming weeks.
The POA made the decision at a special delegate conference of its national executive in Dublin. Delegates voted by a three-to-one margin in favour of recommending acceptance of the deal.
"The outcome of the ballot which will be held on dates to be agreed in the coming weeks, will be verified independently and then published," the POA said in a statement.
Prison officers have been offered essentially the same deal of annualised hours, which they rejected overwhelmingly last April, to cut the €60 million overtime bill. But some tweaks have been made so that prison officers are not forced to work overtime.
The Minister for Justice laid down a 10-week deadline for the prison officers to decide on the deal earlier this month, but he extended it to give the association more time to consider clarifications it had received.
He warned the deal is the final opportunity for prison officers, after 300 meetings with the POA, years of negotiations and the involvement of the Labour Relations Commission.
Mr McDowell said if his proposal is rejected, he will go ahead with his plan to privatise prison escorts and to hand the running of the country's remaining open prisons - Loughan House in Co Cavan and Shelton Abbey in Co Wicklow - to an independent agency.
He has also raised the possibility of getting a private company to run the replacement for Mountjoy Prison in Thornton in Dublin and the new prison planned for Spike Island in Cork.
Additional reporting: PA