The Canadian Auto Workers union has set a strike deadline of 10 a.m. Tuesday for 2,750 workers at Bombardier de Havilland in Toronto who will walk off the job unless an agreement with management is reached on a new contract.

3-month TSX chart for Bombardier

Negotiations began two months ago and will continue overnight, but the prospect of reaching an agreement before the deadline is "increasingly unlikely," the union said Monday.

"Bombardier is trying to walk away from their long-term obligation for retiree benefits, leaving past and current workers vulnerable once they retire," said Jerry Dias, assistant to the CAW national president.

"Bombardier is also trying to erode full-time, permanent employment through the hiring of up to 20 per cent temporary workers," Dias said. "These workers would not be protected by the collective agreement and could be hired or fired as the company saw fit, which is unacceptable."

The union membership includes production workers, skilled trades and office workers at the plane maker's Downsview facility, which produces two complete aircraft — Bombardier's Q400 turboprop and its Global Express business jet — as well as the wing for the Learjet 45.

Shares of Bombardier closed down three cents to $3.32 on the Toronto Stock Exchange.