Rescue and search operations intensified to find 26 people in the town of Atsuma, where Thursday's magnitude-6.7 quake triggered landslides that crushed houses and roads.

At least 16 people were killed and more than 300 injured in the quake, according to central and local government officials.

More than 6400 spent the night in temporary evacuation centres as about 100 aftershocks continued to shake the region.

Meteorological agency official Toshiyuki Matsumori warned that strong quakes could strike the affected areas again within the next six days.

Government spokesman Yoshihide Suga also warned of fresh landslides as heavy rain is forecast for some regions of Hokkaido over the weekend.

The quake caused a blackout across the whole island, resulting in nearly 3 million households losing electricity and affecting hospitals, businesses and traffic lights.

On Friday, more than 1.5 million households remained without power and Industry Minister Hiroshige Seko said it could take up to a week to be fully restored.

The quake came days after Japan was left reeling from the most powerful storm to hit the country in 25 years. Typhoon Jebi battered the western part of the country on Tuesday, killing 11 people and injuring hundreds.

Australian Associated Press