TOKYO - A MODERATE, 5.5-magnitude offshore earthquake hit southern Japan on Wednesday, the US Geological Survey said, although there were no immediate reports of casualties or damage and no tsunami alert was issued.

The quake struck at 4.03am (1803 GMT, 2.03am Singapore time) 142km south-west of the country's remote, Bonin Islands, which lie some 1,000km south of the capital, Tokyo, at a depth of 86km, the US agency said.

Around 20 per cent of the world's most powerful earthquakes strike Japan. -- AFP