TOKYO: A severe tropical storm battered southwestern Japan on Tuesday, knocking out power to tens of thousands of homes, grounding hundreds of flights and injuring nine people.

The Japan Meteorological Agency warned of high waves, landslides and flooding as storm Jangmi which was downgraded from a typhoon rumbles northwards after bearing down on the subtropical island of Okinawa on Monday.

The entire population of Miyazaki city on the island of Kyushu around 390,000 people were urged to evacuate their homes.

Torrential rain and strong winds that felled a 10-metre tree in Okinawa were seen in images reported by local media.

Some 17,000 households on the island and more than 30,000 in the southwestern Kagoshima region were without power Tuesday morning.

Top government spokesman Minoru Kihara said Jangmi had also injured nine people in Okinawa.

Public broadcaster NHK reported that injuries had been caused by Jangmi blowing objects into cars and strong winds causing people to lose their footing.

Kihara warned that public transport in Tokyo and nearby cities could face disruptions Wednesday as the storm approaches.

"For those of you who are living in areas likely to be affected by the storm, please pay close attention to evacuation information issued by your municipalities, and stay mindful of early evacuation," Kihara told a news conference.

"Please remain vigilant and make sure you take action to protect your life."

Japan's two biggest airliners All Nippon Airways and Japan Airlines cancelled a combined 600 flights scheduled for Monday through Wednesday.

Tropical storm

Tropical storm Jangmi injures 9 in Japan, thousands without power