After drilling a small hole in the hull of the ship, the Rocknes, rescue workers managed to pass written notes to some survivors trapped inside, Norwegian newswire NTB reported quoting police sources.

According to Norwegian TV2, two of the crew members were injured.

Two of the 30 crew members were dead, nine people were treated at Bergen hospital, and 19 others were still reported missing more than six hours after the ship flipped over at about 1515 GMT on Monday, according to numbers released by medical sources and the ship's operator, Norwegian Jebsen Management late Monday.

Jebsen Management said the ship's crew was made up of 24 Filipinos, but also included three Dutchmen, two Norwegians and a German.

Numerous boats were sent to the scene of the accident off the coast of Bjoroy in the Raune fjord to rescue survivors.

Three helicopters were also dispatched. 

The accident took place not far off the coast and there were plenty of resources to rescue people, said a spokesman for the rescue services in Sola in southwestern Norway.

According to different witnesses quoted in Norwegian media, some people took refuge on the hull of the ship, while as many as 25 people fell into the sea.

The average water temperature at this time of year is no more than five degrees Celsius.