OTTAWA - Federal Labour Minister Lisa Raitt said Ottawa will order Air Canada flight attendants back to work if talks between the company and union fail to reach a deal and the airline is crippled by a strike.

It is the second time this year that Raitt has threatened to order Air Canada employees back to work.

"We're doing this because it is the best thing for the economy, it's the best thing to do for the Canadian public and it's the best thing to do for the airline," Raitt said Monday night.

Raitt, who met with both sides, said both the union and the airline assured her a deal was possible, but could not guarantee that a strike would be avoided, so she was moving ahead with back-to-work legislation.

The airline and Canadian Union of Public Employees have been engaged in marathon negotiations since early Sunday to avoid a strike.

The roughly 6,800 flight attendants have threatened to walk off the job at 12:01 a.m. Wednesday morning if their demands aren't met.

However the earliest that the minister may introduce back-to-work legislation is Wednesday, so Air Canada may still have to deal with a work stoppage even with the move by the minister.

"That's why we are acting now to minimize that amount of time and minimize the effect on the economy," Raitt said.

NDP Labour critic Yvon Godin said the government is taking away the workers' right to negotiate.

"The strike is even not started yet and she's already telling Canadians in this country under the Conservative government there's no strike," he said.

However, Godin stopped short of promising a filibuster to delay any back-to-work legislation proposed by the government. The NDP launched a filibuster earlier this year to protest the legislation forcing postal workers back to work.

Air Canada spokesman Peter Fitzpatrick said the talks were progressing.

"We're close and committed to reaching a negotiated agreement which is preferable to back-to-work legislation for all parties concerned," Fitzpatrick said.

"We've shown that we can achieve negotiated settlements and Parliament should be left to running the country."

A walkout in June by the airline's customer service agents lasted just three days before a deal was reached under a threat by Raitt that she would legislate them back to work.

While the strike by customer service agents slowed operations for the airline in June, Air Canada did not cancel any flights. A strike by the flight attendants would cripple Air Canada. The airline has yet to disclose its contingency plans in the event of a strike, but has said it would operate a partial schedule with the help of its codeshare partners.

Jazz will also continue to operate regional connector service for Air Canada since its flight attendants operate under a separate contract.

Air Canada is allowing travellers who are to booked to fly over the next six days to change their flights free of charge to a later date, subject to availability.

In August, the Air Canada flight attendants resoundingly rejected a tentative deal CUPE negotiated with the airline, forcing the two sides back to the drawing board.

The key areas of dispute are wages, pensions, crew rest, working conditions and work rules.