An earthquake that struck in the Queen Charlotte Islands region off the west coast of Canada has generated a tsunami that is heading towards Hawaii, the Pacific Tsunami Warning Center said.

The first tsunami wave was expected to arrive in the Pacific island state at 10.28pm local time on Saturday (7.28pm AEDT Sunday), the Hawaii-based centre said.

Residents were advised to evacuate coastal areas, and warning sirens sounded across the Hawaiian islands.

Centre officials told CNN that waves of one to two metres were expected.

"Basically this tsunami is pointed right at us," Gerard Fryer, the centre's senior geophysicist, said on CNN.

The tsunami waves could wrap around the islands so all shores were at risk, the centre said, adding that the tsunami could consist of multiple waves.

The warning was issued after a magnitude 7.7 earthquake struck off the Queen Charlotte Islands late on Saturday.

No reports of casualties or damage were reported on the sparsely inhabited islands.

The West Coast-Alaska Tsunami Warning Centre also issued a warning for the coasts of British Columbia and Alaska.