Air Canada is seeking financial compensation from the union representing its 6,800 flight attendants, amid an allegation that union brass have been negotiating in bad faith.

The airline said Thursday afternoon that the Canadian Union of Public Employees hasn't done enough to ensure that a new contract is ratified by union members, who have been in a long-running dispute with Canada's largest air carrier.

"Though the company was given assurances of unanimous support from the CUPE leadership for the first tentative agreement, individual base presidents remained silent or expressed views against ratification during the ratification process," Air Canada stated.

The airline, which has submitted the unfair practice complaint to the Canada Industrial Relations Board, did not say how much it was seeking in compensation.

The salvo is the latest in a bitter labour battle that has pitted the airline against its employees, with the federal government wading in with a controversial decision to quash a potential strike this week.

In response to Ottawa's intervention, flight attendants staged a noisy protest at the Toronto-area office of Labour Minister Lisa Raitt Thursday, decrying her decision to bar workers from striking.

In a symbolic show of defiance, the protesters at Raitt's Milton constituency office shouted slogans like "negotiate, don't legislate," and held banners carrying messages such as "R.I.P. Labour Rights."

Flight attendants were due to strike on Thursday morning, after they rejected a deal that union negotiators had brought to them to ratify. It was the second time a deal was rejected.

But before they could walk off the job, Raitt submitted two referrals to the CIRB that suspended the flight attendants' right to strike.

Raitt's two referrals ask the board to determine if flight attendants provide essential services, and to consider whether it should impose a settlement or send the dispute to binding arbitration.

Sid Ryan, head of the Ontario Labour Federation, rallied the striking workers at Raitt's Milton office and said that flight attendants have already made concessions to the airline.

Ryan, an ex-leader of CUPE, pointed to a 20-per-cent wage cut that flight attendants took in 2004.

"The labour movement is always accused, that somehow, the leadership are leading the membership around by the nose," Ryan said through a megaphone.

"And in this case you've proven twice that it's the membership that are in control, it's the membership that makes the decisions," he said, adding that each flight attendant has given back about $8,000 in wages through a series of rollbacks.

Raitt was not at her constituency office, which is about 50 kilometres northwest of Toronto.

Elsewhere, the union representing Air Canada's 6,800 flight attendants also called for a Thursday demonstration at the Montreal airport, just hours after its members were supposed to be forming a picket line at the very same location.

In advance of Thursday's planned demonstrations, Air Canada said it was "business as usual" for the airline, as flights were taking off as scheduled.

Mounting tension between union, members

While the flight attendants were following the advice of their union and showing up for work on Thursday, there is clear evidence that there is also a disconnect between the workers and their union representatives.

The rejection of the recent contract offer from Air Canada was the second deal the flight attendants turned down in the past three months.

Retired labour leader Buzz Hargrove said the back-to-back rejections are an indication that the flight attendants have lost confidence in the union leadership.

"This is a very unfortunate situation at this point," Hargrove told CTV News Channel on Thursday.

Labour lawyer Howard Levitt said the union had failed to make its members aware of the necessity of making a deal with their employer.

"They need the contract that the union executive agreed to and the union executive was irresponsible in not bringing along their membership," Levitt told CTV News Channel.

Latest labour scuffle for Ottawa

The push to keep the flight attendants from striking is the latest dispute in which Ottawa has intervened in a labour dispute in recent months.

Other examples include the recent Canada Post strike, which ended when the government passed back-to-work legislation, and the prior job action at Air Canada when customer service staff walked off the job this summer.

"There's a feeling that the Tories have used this technique of back-to-work legislation, or loopholes like this one, to take away the right to strike," CTV's Roger Smith said.

"The feeling is that employers aren't going to negotiate in good faith if they think the government is going to come along and bail them out with back-to-work legislation."

With files from The Canadian Press