Winnipeg's transit union is banning its members from signing up for additional overtime, its first stage of legal job action, after rejecting the City of Winnipeg's second contract offer.

Members of the Amalgamated Transit Union Local 1505, which represents about 1,400 drivers, mechanics and other Winnipeg Transit workers, voted to reject the four-year deal last week.

The ban on overtime won't apply to late or missed relief buses, only to voluntary overtime that operators currently have the option of signing up for.

The deal, which the City of Winnipeg said was its final offer, included three annual wage hikes of 1.75 per cent. Members voted against the deal by a margin of 97 to three per cent, said Aleem Chaudhary, the union's president.

Chaudhary said he's hoping the city will come back to the negotiating table to work out a new deal.

At this point, the main issue for the union is working conditions, he said.

He said he didn't know how long this stage of job action will last, and that the union isn't prepared to say whether or not they are planning to escalate it if contract negotiations with the city aren't successful.

"We're hoping we don't have to escalate it any further. We're hoping that the city will come and sit down with us and work out a deal," he said.

Transit drivers also staged a job action on May 14, when they declined to enforce fare payment, a move that cost the city approximately $45,000 in lost revenue.

In April, the union rejected a previous city contract offer. This placed the union in a strike position; it's unclear if the city is considering a lockout.

They've been without a collective bargaining agreement since January.