GO Transit bus operators, support staff and ticket agents could disrupt service for hundreds of thousands of passengers next month after they overwhelmingly rejected the company's latest contract offer.

The unionized employees, who are represented by the Amalgamated Transit Union, voted 96 per cent against the deal late Tuesday night, putting the workers in a legal strike position on Dec. 10.

Wages and job security are key issues in the negotiations.

The possible job action doesn't directly affect GO train operators, but a union official said the striking workers will set up pickets at GO Transit stations to disrupt service.

GO Transit moves about 165,000 commuters every day, with its 1,800 buses transporting about 30,000 passengers. About 75 per cent of riders travel to and from Toronto.

A union official told CTV's John Musselman the strike may be averted, but time is ticking.

"We'll have to go back to the company to try to get this resolved, and if we can't get it resolved, then at 12:01 a.m. on Dec. 10, we'll be in a strike-lockout position," union official Denis Tanham said on Wednesday.

A provincial conciliator will meet with both sides on Dec. 5 to try and hammer out a collective agreement.

With a report from CTV's John Musselman