The Norwegian Competition Authority has approved a merger of three offshore vessel owners backed by John Fredriksen and Kjell Inge Rokke.

Deep Sea Supply, Farstad Shipping and Solstad Offshore expect to seal the deal on or near 9 June, two of the Oslo-listed companies said today.

The companies are aiming to create the world's largest owner of "high end" offshore vessels with a fleet of 154 ships.