TOKYO (AFP) - A 6.1-magnitude earthquake hit off Japan's Bonin Islands on Friday (Sept 8) but there was no tsunami risk, seismologists said.

The quake hit at a depth of 450km at 2.27am (1.27am Singapore time) 770km south of Shimoda, according to the United States Geological Survey.

Japan Meteorological Agency said the quake poses no tsunami risk.

A 9.0-magnitude earthquake in March 2011 triggered a massive and deadly tsunami, which smashed into a power station and sparked the world's worst atomic accident since Chernobyl in 1986.

Tokyo Electric is working to clean up and dismantle the reactors in a process that is expected to take at least four decades.