The helicopter was carrying workers from an oil platform to the mainland crashed off the coast of Hordaland, in the city of Bergen, according to police.
Two people were still missing when rescue operations stopped Friday afternoon.
Meanwhile, Norway’s civil aviation authority has imposed a flight ban on the type of helicopter that crashed – the Eurocopter (EC) 225L Super Puma. Reports say it was “totally destroyed”.
The aircraft was carrying 11 Norwegians, one Briton and one Italian, rescue services said.
The helicopter broke into pieces near a small island and parts of the wreck were found scattered on land and at sea.
This was “one of the most severe helicopter accidents in the history of the Norwegian oil industry,” said Statoil’s Arne Sigve Nylund, executive vice president development and production Norway.
On the other hand, Norwegian Prime Minister Erna Solberg also said news of the crash was “horrible”.