Japan issued tsunami alerts and ordered evacuations following a series of earthquakes on Monday that started a fire and trapped people under rubble on the west coast of its main island.

The Japan Meterological Agency reported more than a dozen quakes off the coast of Ishikawa and nearby prefectures shortly after 4pm (local time), one of them with a preliminary magnitude of 7.6.

The agency issued a major tsunami warning for Ishikawa and lower-level tsunami warnings or advisories for the rest of the western coast of the island of Honshu, as well as the northernmost of its main islands, Hokkaido.

However, later tonight Japan dropped its tsunami alert but told residents of coastal areas not to return to their homes as deadly waves could still come.

The agency initially issued a major tsunami warning for Ishikawa and lower-level tsunami warnings or advisories for the rest of the western coast of the island of Honshu, as well as the northernmost of its main islands, Hokkaido.

The warning was downgraded to a regular tsunami several hours later, meaning the waters could still reach up to 3 metres. Aftershocks could also slam the same area over the next few days, it said.

Japanese public broadcaster NHK TV initially warned torrents of water could reach as high as 5 metres.

NHK said the tsunami waves could keep returning, and warnings were continuing to be aired hours after the initial alert. Several aftershocks also rocked the region.

Hayashi stressed that it was critical for people in coastal areas to get away from the oncoming tsunami. “Every minute counts. Please evacuate to a safe area immediately,” he said.

People returning to get their wallets and other belongings have been known to be swept away and drowned even hours after the first evacuation warning. People were evacuated to stadiums, where they will likely have to stay for a few days.

At least six homes were damaged by the quakes, with people trapped inside. A fire has broken out in Wajima City, Ishikawa Prefecture, and electricity is out for more than 30,000 households, Hayashi said.

He said no reports of deaths or injuries had been confirmed, saying the situation was still unclear. Japan's military was taking part in the rescue efforts, he said.

Japanese media footage showed people running through the streets, and red smoke spewing from a fire in a residential neighbourhood. Photos showed a crowd of people, including a woman with a baby on her back, standing by huge cracks that had ripped through the pavement.

Bullet trains in the area were halted. Parts of the highway were also closed, and water pipes had burst, according to NHK. Some cell phone services in the region weren't working.

The Meteorological Agency said in a nationally broadcast news conference that more major quakes could hit the area over the next week, especially in the next two or three days.

More than a dozen strong quakes had been detected in the region, with risks of setting off landslides and houses collapsing, according to the agency.

Takashi Wakabayashi, a worker at a convenience store in Ishikawa Prefecture, said some items had tumbled from the shelves, but the biggest problem was the huge crowd of people who had shown up to stock up on bottled water, rice balls and bread.

“We have customers at three times the level of usual,” he said.