Air Canada said on Sunday it had suspended plans to restart operations after a union representing flight attendants said it would continue to strike.

The continued stoppage defies an order from the Canada Industrial Relations Board (CIRB) that was requested by the Canadian government and would have had staff return to work by 2:00 p.m. Ottawa time (1800 UTC/GMT) on Sunday.

The Canadian flag carrier said it planned to resume operations on Monday evening instead.

What did the union say about the Canadian flight attendants' strike?

In a statement, the union invited Air Canada back to the table and called on the employer to "negotiate a fair deal."

"Our members are not going back to work," Canadian Union of Public Employees (CUPE) chief Mark Hancock said while speaking outside the Pearson International Airport in Toronto.

"We are saying no," he declared.

Hancock called the negotiation process "unfair" and argued that the return-to-work order was unconstitutional. He believed the firm refused to negotiate because it expected government support.

Some 700 daily flights were suspended on Saturday due to the strike, with over 100,000 passengers stranded.

The CUPE union had demanded that flight attendants be paid for time spent on the ground between flights and helping passengers on board.

Currently, the workers are paid only when they are flying.

Union defies government-ordered arbitration

The union also criticized CIRB chair Maryse Tremblay for not recusing herself from the case, saying that her previous work as Air Canada's counsel represented a conflict of interest.

The return to work order came after the Canadian government asked the CIRB to impose binding arbitration.

Air Canada said that the CIRB had ordered the terms of a collective agreement between the union and the airline that expired on March 31 to be extended until a new deal is reached.

Edited by: Rana Taha