Three people are dead and four others remain missing after a sea plane crashed into a lake in the Eastern Canadian province of Newfoundland and Labrador.

Air Saguenay President Jean Tremblay said on Tuesday the de Havilland DHC-2 Beaver was carrying four fishermen, two guides and the pilot.

It left Three Rivers Lodge on Crossroads Lake, east of Schefferville, Quebec, on Monday morning headed to a remote fishing camp on Mistastin Lake in Labrador. The plane didn’t return as planned that evening.

The identities of those on the flight weren’t immediately made public.

The wreckage was spotted from a Hercules aircraft at about 5am local time on Tuesday. It was submerged about 1.6km from the shore, identified by the visible tail and other wreckage in the water.

Rescue officials said two search helicopters, a Cormorant and a Griffon, were sent to the site, and a second float plane was also dispatched to assist in search efforts.

Major Mark Gough of Maritime Forces Atlantic, which is coordinating the rescue effort, said it’s still unknown what time the plane when down.

“If someone was to have survived the crash they would have had a bit of a swim to get to land,” Mr Gough said

The cause of the crash remains unclear but Mr Gough said “the weather was fair, sunny with cloudy periods and light winds” on Monday and continued much the same on Tuesday.

The Canadian Transport Safety Board said it would deploy a team of investigators to gather information about the crash.

-AAP