The Veterinary Officers Association has become the eighth public service union to reject the Croke Park II proposals.
Earlier, the Irish Federation of University Teachers and the Civil, Public and Services Union voted against the deal.
Members of the IFUT union rejected the proposals by a margin of three to one, while the Civil Public and Services Union also overwhelmingly rejected the agreement.
A total of 86.7% of members voted to reject the deal, with 13.3% in favour.
The turnout was 82%.
Meanwhile, UCATT which represents around 2,000 craft workers in local authorities and the health sector has gone against the advice of its union executive and rejected the deal.
The margin of rejection was 62% against, and 38% in favour.
It brings to seven the number of public service unions that have so far rejected the deal.
The others include the Teachers' Union of Ireland, the Technical Engineering and Electrical Union, the Medical Laboratory Scientists Association and the Association of Higher Civil and Public Servants.
However, two smaller unions - construction union BATU and the plasterers' union OPATSI - announced this morning that they are accepting the proposals.
The unions that could make or break the deal are SIPTU, IMPACT and the Public Service Executive Union, which have recommended a Yes vote.
The INTO with 35,000 members is also significant, though its executive did not issue any recommendation for or against.
Those key unions will reveal the results of their ballots tomorrow, while the Public Services Committee of Congress will meet on Wednesday to deliver the overall result of the vote.
If the proposals are rejected, the Government has threatened to legislate for across the board pay cuts of around 7%.