Labour Minister Lisa Raitt has asked the Canadian Industrial Relations Board to investigate Air Canada's disputes with two of its unions — pilots and ground staff — a move that will buy time to reach agreement and avert a strike and lockout threatened for midnight Sunday.

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.

The minister said it was the ninth time this fiscal year that she has asked the CIRB to get involved in a dispute between a company and its employees.

In October, Ottawa got the board to investigate the dispute between Air Canada and its flight attendants. At the time, the move blocked flight attendants from going on strike, despite a mandate to do so. The board ultimately never issued a ruling in that case, as the union and the airline opted to go to binding arbitration to reach a new collective agreement.

Threat of pilots lockout

Raitt's move Thursday came on the heels of an Air Canada announcement earlier in the day that it would lock out its 3,000 pilots Sunday at midnight Eastern Time. The airline's 8,600 machinists, electricians and baggage handlers had already served notice that they would go on strike at that time.

Although Raitt stopped short of suggesting Ottawa would implement back-to-work legislation in both cases, she urged all sides to come up with a deal at any cost.

"The best deal they get is the one they do themselves," she said.

"I think Air Canada management and unions should take a lesson from this and determine what their own labour relations are like. Because it's not the role of the Canadian government to put this much effort all the time into one single company," Raitt said.

"We have other things to do."

There are signs that Ottawa's pressure might be working, as Bill Trbovich of the International Association of Machinists and Aerospace Workers told CBC News Thursday that his union's bargaining team has been reassembled in Toronto to meet with Air Canada's negotiators.

Trbovich says the threatened strike deadline is focusing the minds, and putting pressure on both sides to reach a contract settlement

In the other dispute, CBC News has learned that the Air Canada Pilots Association is also meeting with Air Canada officials, at a site near Pearson International Airport just outside Toronto.