The quake has also triggered power blackouts across a wide area in Hokkaido affecting some 3 million households, and hundreds of thousands of households were reported as having no water supply.

Telephone services and television broadcasting in Sapporo were affected, and flights were cancelled at New Chitose Airport due to the power outage, and bullet train and local train services were also disrupted.

More than 1,300 public schools in the prefecture have decided to temporarily close and asked their students to stay at home, according to local reports.

The Japanese government has set up a liaison unit at the crisis management center of the prime minister's office to gather more information on the quake.

It said that some 25,000 personnel from the Japanese Self-Defense Forces will be dispatched to the quake-stricken areas for rescue and relief operations at the request of the governor of Hokkaido.