Members of the IMPACT trade union have voted to accept the new public sector pay agreement by a margin of 77% to 23%.
Representing 60,000 workers, IMPACT is the country's largest trade union. 50,000 of its members work in the public sector.
In a statement following the announcement of the result, the union said discussions to address pay iniquities for members of the public service who joined after January 2011 should begin immediately if the Irish Congress of Trade Union backs a proposal later this year.
The Public Service Stability Agreement facilitates negotiations on the so-called 'new entrants' issue.
The PSSA is to be discussed by ICTU's Public Services Committee on 18 September.