The ministry did not name the victims of Sunday's crash on the rugged North Shore of the Gulf of St Lawrence.
The Foreign Office said today that British officials were in contact with Canadian authorities, and "our consular officers are ready to provide assistance."
An official with operator Air Saguenay said the Beaver seaplane was on a sightseeing flight from Lac Long in Tadoussac, 480 kilometers northeast of Montreal, when it crashed. He said weather conditions were excellent at the time.