The Canada Industrial Relations Board has declared a strike by 10,000 Air Canada flight attendants illegal and ordered them back on the job after they ignored an earlier order to return to work and submit to arbitration.

Canada's labor tribunal on Monday declared a strike by Air Canada's flight attendants illegal, a decision that could end a work stoppage which has cancelled travel for half a million people worldwide.

The Canada Industrial Relations board ordered the flight attendants union to call off the job action by midday.