The 1,989-tonne Belize-flagged cargo ship Guoxing 1 was carrying some 3,000 tonnes of iron scrap and rapidly took in water after the hit, Japan Coast Guard spokesman Tomoyuki Hanzawa said.

The collision between the Guoxing 1 and a 138-tonne Japanese fishing boat happened around 10 p.m. GMT on Saturday and the cause is unknown, he added.

The Guoxing 1 had a crew of 14 Chinese and Vietnamese nationals, of which 13 are still missing and the coast guard is searching for them, Hanzawa said.

One Vietnamese crew member was rescued by a nearby ship, while the 15 Japanese crew members of the fishing boat are safe.