AT least nine people have died and hundreds have been injured in a powerful earthquake that hit Japan’s northernmost island of Hokkaido.

Officials said at least 366 people were injured, five of them seriously, with another 30 unaccounted for after the magnitude 6.7 earthquake caused dozens of landslides to crush homes at around 3am on Wednesday.

The quake’s epicentre was east of the city of Tomakomai, but shaking buckled roads and damaged homes in Sapporo, Hokkaido’s prefectural capital, which has a population of 1.9 million.

Nearly three million households were left without power in what is the latest in an exhausting run of natural disasters for Japan.

Normal business on the island was paralysed by the tremor, as blackouts cut off water to homes, immobilised trains and airports, caused hundreds of flight cancellations and shut down phone systems.

In the town of Atsuma, rescuers used diggers and shovels to search for survivors under tonnes of earth that tumbled down steep mountainsides, burying homes and farm buildings below.

Aerial views showed dozens of landslides in the surrounding area, with practically every mountainside a raw slash of brown amid deep green forest.

Reconstruction minister Jiro Akama told reporters that five people were believed to be buried in the town’s Yoshino district.

Some of the 40 people stranded there were airlifted to safer grounds, NHK said.

Twenty-eight people remained unaccounted for in the town, Atsuma mayor Shoichiro Miyasaka told public broadcaster NHK.

The landslides had ripped through some homes and buried others. Some residents described waking up to find their next-door neighbours gone.

“The entire thing just collapsed,” said one witness. “It’s unbelievable.”

The island’s only nuclear power plant, which was offline for routine safety checks, temporarily switched to a back-up generator to keep its spent fuel cool.

Nuclear regulators said there was no sign of abnormal radiation – a concern after a massive quake and tsunami in March 2011 that hit north-east Japan and destroyed both external and backup power to the Fukushima Dai-ichi nuclear plant, causing meltdowns.

Economy, trade and industry minister Hiroshige Seko told reporters that damage to generators at the coal-powered Tomato Atsuma plant meant that the restoration of power could take more than a week.

In the meantime, authorities sent power-generator vehicles to hospitals and other locations.

Following this latest quake, many roads were closed and some were impassable. Broadcaster NHK showed workers rushing to clean up shattered glass and reinstall ceiling panels that had fallen in the region’s biggest airport at Chitose.

Prime minister Shinzo Abe said that 25,000 troops and other personnel would be dispatched to the area to help with rescue operations.

Reacting quickly to the disaster, the troops deployed water tanker trucks in Sapporo, where residents were collecting bottles to tide them over until electricity and tap water supplies came back online.

The earthquake had a wide impact, affecting the scenic town of Biei to the north, where residents lined up outside of stores and quickly cleared shelves of essentials like water, toilet paper and food.

“Only a few cartons of instant ramen were left,” said Mika Takeda, who lives in the town of 10,000.

Japan is used to dealing with disasters, but the last few months have brought a string of calamities.

The quake came days after typhoon that lifted trucks off their wheels and triggered major flooding in western Japan, leaving the main airport near Osaka closed after a tanker rammed a bridge connecting the facility to the mainland.

Dozens also died when the summer brought devastating flooding from torrential rains in Hiroshima.