The man, in his 30s, is reported to have fallen ill and was collected by a CHC-owned helicopter at around 8am on Wednesday morning to be taken to Bergen, Norway.

The man is reported to have then exited the helicopter not far off the coast, falling 600m to his death in the North Sea.

A search-and-rescue mission found the man an hour later.

A medical attendant and two pilots were on board the helicopter, said to have been joined by a lift operator and rescue worker.

Some media has reported that the man was working for Kaefer Energy on the platform.

The incident is being investigated by police, Statoil and CHC.