Man-Yi, the fourth typhoon of the season, cut off electricity supply at 60,000 households in the Okinawa archipelago by Friday midmorning.

"The winds are so strong. Our staff are on standby at branch offices, waiting for the winds to calm down," a spokeswoman at Okinawa Electric Power said.

Man-yi, described as "extremely strong" by the meteorological agency, is packing wind gusts of up to 252 kilometres an hour (156 miles an hour) and whipping up waves of more than nine metres (30 feet).

The storm off the coast of the island was near the Okinawan capital of Naha at 10:00 am (0100 GMT) and moving north at 20 kilometres (12.4 miles) an hour.

The typhoon may cross the Tokyo region early Sunday after lashing western Japan, the meteorological agency said.

The agency has also warned of torrential rain, flooding and landslides.

Airline companies have cancelled 245 flights with the number set to increase, according to public broadcaster NHK.

Man-Yi is named after a strait that is now a reservoir in Hong Kong.

Japan and other nations in the western Pacific are hit each year by lethal typhoons. Last year, Typhoon Shanshan killed nine people in Japan and injured 300 others.