A powerful typhoon hurtled toward Japan's mainland Sunday after injuring dozens on southern islands, as weather officials warned that fierce winds and torrential rain could trigger landslides and floods.

The storm is forecast to smash into the mainland near the city of Osaka shortly after 6pm (0900 GMT) and churn across the Japanese archipelago, likely hitting areas still recovering from extreme weather that has battered Japan in recent months.

Trami tore through the southern island of Okinawa on Saturday, bringing winds strong enough to flip over cars. Several houses were flooded or damaged and 46 people on the island sustained minor injuries but no one was feared dead, local officials said.

Nationwide, authorities have issued non-compulsory evacuation advisories to 1.5 million residents, according to public broadcaster NHK. Nearly 500,000 households in Kyushu and Okinawa have lost power, local utilities said.

As the typhoon barrelled east, rail authorities took the highly unusual step of cancelling evening train services in Tokyo, one of the world's busiest networks, urging passengers to shelter indoors when the storm hits.

The typhoon is not expected to hit the capital head-on but strong winds and heavy rain are still feared from later Sunday. Some businesses were already putting up shutters and hunkering down.

Trami is the latest in a string of extreme natural events in Japan, which has suffered typhoons, flooding, earthquakes and heatwaves in recent months, claiming scores of lives and causing extensive damage.

Packing maximum gusts of 216 kilometres (134 miles) per hour, Trami was expected to travel over most of the archipelago, weakening slightly but causing extreme weather into Monday, forecasters said.

Still classed as a "very strong" typhoon, Trami pounded Kagoshima on the western tip of Japan early Sunday, causing 10 minor injuries -- such as cuts from broken windows and people knocked over by gusts.

"We are strongly urging our residents to stay indoors because it is extremely dangerous to be outside now," Masaaki Tamaki, an official of Kagoshima's disaster management section, told AFP.