Garda Sergeants and Inspectors will refuse to work an extra 30 hours a year from the 1st of January.
The Association of Garda Sergeants and Inspectors says the unpaid overtime - introduced under the previous Haddington Road pay deal - should be expiring in January.
AGSI members voted against the new Lansdowne Road deal on public sector pay, and are also set to face a pay freeze from next July as a result.
In a statement this morning the AGSI says it has no confidence in the Lansdowne Road deal being honoured, and that it will advise members to stop taking on extra working hours from January.
In a statement, AGSI Deputy General Secretary John Jacob said, “we had hoped that following discussions with the Minister for Justice Frances Fitzgerald two weeks ago and DPER last week, we would have our concerns taken on board, however they have offered us no solution to this impasse.
"We suffered pay cuts, worked 30 hours for free and engaged fully in [Haddington Road] Agreement to help the Government turn the economy around during the worst financial crisis this country has witnessed. Despite this we are threatened with an incremental pay freeze at a time when we should be working together to improve morale within the force - morale which is extremely low and which has been recognised as such by our Commissioner," he added.