Seoul: At least 13 people are dead and two are missing after a fishing boat collided with a refuelling vessel and capsized off the west coast of South Korea.

An official from the Korea Coast Guard said seven people were rescued and the two missing included the boat's captain.

He said 22 people were aboard the 9.8-tonne South Korean fishing boat that capsized after colliding with the 336-tonne refuelling vessel in waters off the port city of Incheon.

The refuelling vessel did not suffer damage.

President Moon Jae-in ordered all measures be taken to find those missing, his office told reporters.

Those rescued from the water have been sent to nearby hospitals, the coast guard said.

The reason for the collision has yet to be confirmed, according to the coast guard.