As previously reported, Conservative councillors have threatened to end the public funding of two full-time union posts and stop giving unions use of council offices, estimated to be worth up to £90,000 a year.
Opposition councillors refused to back the move, saying it was poorly timed and would sour industrial relations.
Labour said union reps saved the council money by helping to resolve employment disputes early.
Unions have called the proposal a “vindictive attack” by council leader Royston Smith after members launched industrial action over pay cuts imposed on council workers last summer.
Cllr Smith denied the charge and said the council would continue to give union officials time off to perform their duties.
But he said it was not right that tens of thousands of pounds of city taxpayers’ money was funding union officials to represent 2,500 members at the council.