MALAYSIAN cargo ship, Genius Star-VI, sank 300 kilometres south of the Indian port city of Haldia on April 13.

Indian coast guard vessels rescued 11 of the 17 crewmembers, the New Kerala news service reported.

The cause of the accident is still unknown but the search for the six remaining crewmembers has been stepped up with a Dornier aircraft and two coast guard ships patrolling the Bay of Bengal.

An Indian coastguard spokesperson was quoted by the news service as saying the ship probably sank because it was too old.

The Genius Star-VI had an all-Chinese crew and those rescued were brought to Haldia and were said to be in good health.