Rescue services lifted 18 passengers and crew to safety yesterday after a civilian helicopter ditched in the North Sea off the east coast of Scotland.

"All 18 are safe," a Coastguard spokesman said.

Fifteen were taken by lifeboat to an offshore oil platform and three were airlifted to safety.

The Super Puma helicopter went down about 190 kilometres off the port city of Aberdeen as it was approaching an offshore oil installation, a Defence Ministry spokesman said.

The cause of the crash was not immediately clear.

Three military helicopters and a Nimrod aircraft took part in the search operation. Winds were light at the crash site but the swell was two to three metres high, making rescue attempts difficult, the coastguard said.