Raitt told reporters in Ottawa on Thursday that she will ask the board to investigate what a work stoppage would mean to Canadians, based on "health and safety concerns."

"Air Canada can carry some cargo that is related to the health industry, related to pharmaceuticals, and certainly those kinds of things related to remote communities that, simply put, nobody else flies to because Air Canada has jurisdictional responsibility to fly to certain remote areas," Raitt told CBC News.

"The other side of it, of course, is passengers and whether or not people rely upon that link to get to life-saving treatments that they need to have in other parts of Canada."

Referral of the matter to the industrial relations board bars the airline and its unions from undertaking a work stoppage while the board is investigating.

On its website, Air Canada said that there will be no disruption of service and that its full schedule remains unchanged.

"We thank our customers for their patience and loyalty during this time," the company said. "Customers should continue to book with confidence."

Raitt said she did not know how long it would take the board to conduct its investigation. Continued...