Two crew have died and another has been injured after a gas leak on a Cosco bulker, Indian police said.

The PTI news agency cited officers as saying two Chinese men were killed in the incident on the 63000-dwt Feng Hui Hai (built 2017) near Jamnagar on Monday.

The vessel was en route from Singapore to Navlakhi in Gujarat with coal.

"Prima facie, the two Chinese died due to gas leakage on the ship," a police official said.

Three men had passed out on board and were brought ashore by a tug.

The third seafarer was undergoing treatment in hospital.

The vessel remained anchored off Jamnagar on Monday.

The dead men were named as Zhang Baohai, 55, and Dong Kui, 32.