A Japanese chemical tanker has collided with a cargo vessel off the coast of south-western Japan.

No-one was injured among the six Japanese crew aboard the tanker Ryoshinmaru, or among the 14 Chinese crew on the Belize-registered cargo ship Xin Hai 99.

The crash early on Saturday is under investigation and both ships are anchored in the area, about 2.2 miles off the coast of Wakayama Prefecture.

Ship damage
The Xin Hai 99 cargo ship was damaged in the collision (Kyodo News/AP)

A Kushimoto Coast Guard official said some oil leaked from the engine area of the cargo ship, which initially started to sink, but it was brought under control.

The tanker had left Kobe port to pick up chemicals from another Japanese port and did not have any chemicals on board at the time of the accident.

Divers are being sent to the scene and GPS records are being pursued to determine the cause of the accident.

The Chinese crew told the coast guard the tanker had suddenly veered towards them, the official added.