TOKYO (AFP) - Authorities have lifted a tsunami warning for islands in Japan's far south on Monday after a 6.6 magnitude earthquake struck off eastern Taiwan.

National broadcaster NHK had earlier put in place a warning that waves as high as one metre were possible on several islands in the southern Okinawa chain after a very shallow quake centred on Yonaguni in the southwest, near Taiwan.

Witnesses said buildings swayed in Taipei but there was no visible damage in the Taiwan capital.

NHK had reported that the tsunami - an irregular wave that alters the sea level, and not necessarily a huge event - had already arrived at remote Yonaguni, although no details on the extent of the waves were immediately available.

Live footage from coastal cameras showed sea levels had apparently not risen in several harbours within the warning zone.

The Pacific Tsunami Warning Centre said in a statement that "based on all the available data... there is no tsunami threat from this earthquake."

The US Geological Survey said the 6.6 magnitude quake, which Japanese authorities had originally put at 6.8, struck 71 km east of Hualian, Taiwan at 9.43 am Singapore time.

Japan sits at the confluence of four of the earth's tectonic plates and registers more than 20 per cent of the planet's most powerful earthquakes every year.

Strict building codes and a long familiarity with the dangers mean that quakes that might cause devastation in other parts of the world are frequently uneventful in Japan.

However, occasional disasters prove exceptionally deadly, and more than 18,000 people were killed by a huge tsunami that smashed into the northeast coast in 2011 after a huge 9.0 magnitude earthquake.