The union representing Ottawa transit workers urged its 2,300 members to reject the city's offer during Thursday's vote that was ordered by the federal government.

"Please, vote No," the Amalgamated Transit Union Local 279 said Sunday on its website. "Your future, your families future and your union's future depends on this vote."

The supervised vote, ordered by federal Labour Minister Rona Ambrose to be held no later than Jan. 9, will be conducted by the Canada Industrial Relations Board on Thursday beginning at 6 a.m. ET, the union said.

Over the weekend, the city took out full-page advertisements in Ottawa's major newspapers to bring the information directly to union members, who walked off the job on Dec. 10, the Ottawa Sun reported.

The head of the Amalgamated Transit Union Local 279 accused the city of trying to break the union, the Sun reported.

"It's just to show again how they try to undermine the union, and to try to negotiate with our members instead of trying to negotiate with the union," said president André Cornellier, adding the union will hold a meeting for members Monday at 10 a.m. ET and urge them to reject the deal.

The city has proposed a salary increase totalling 7.25 per cent over three years, additional leave days and what it called a $2,500 productivity bonus, something many bus drivers referred to as a "bribe," the Sun reported.

The ad campaign was designed to deliver information directly to union members who may not be getting full details on the contract offer from the union executive, Alain Mercier, director of transit services told the Sun.

"We're trying to demonstrate both to our own employees and to the public the reasonableness of the city's position," he said. "I think there's been a lot of rhetoric after talks broke off."

If the contract is ratified, Mercier said transit workers could be back to work within a week.

With files from the Canadian Press