Japan fights 'battle against time' to rescue earthquake survivors as death toll rises

Japan on Tuesday struggled to assess the full extent of damage from an earthquake that struck its west coast, killing several people, wrecking buildings and roads and knocking out power to swathes of homes in freezing temperatures.

The quake with a preliminary magnitude of 7.6 struck in the middle of the afternoon Monday, prompting residents in some coastal areas to flee to higher ground as tsunami waves about one metre hit Japan's western seaboard.

Thousands of army personnel, firefighters and police officers from across the country have been dispatched to the worst-hit area in the relatively remote Noto peninsula.

However, rescue efforts have been hindered by badly damaged and blocked roads and one of the area's airports has been forced to close due to cracks in the runway. Many rail services and flights into the area have also been suspended.

"The search and rescue of those impacted by the quake is a battle against time," Prime Minister Fumio Kishida said during an emergency disaster meeting on Tuesday.

Kishida said rescuers were finding it very difficult to reach the northern tip of the Noto peninsula due to wrecked roads, and that helicopter surveys had discovered many fires and widespread damage to buildings and infrastructure.

Public broadcaster NHK said eight deaths had been reported in the hard-hit town of Wajima near the quake's epicentre, while in nearby Suzu some doctors were unable to reach a hospital that was relying on a backup generator for power.

The national police agency said six people had been confirmed dead, and the fire and disaster management agency said 19 people were in a state of cardiac arrest.

More than 90 tremors have been detected since the quake first hit on Monday, according to the Japan Meteorological Agency. The agency has warned more strong shocks could follow in the coming days.

A quake with a preliminary magnitude of 5.6 shook the area as Kishida was speaking on Tuesday. 

In Toyama city, around 100 kilometres from the worst-hit area, some shelves in convenience stores were empty as the disaster disrupted the delivery of goods across the region.

The Japanese government ordered more than 97,000 people to evacuate their homes on Monday night, sending them to makeshift evacuation centres in sports halls and school gymnasiums.

Many returned to their homes Tuesday as authorities lifted tsunami warnings.

But around 33,000 households remained without power in Ishikawa prefecture early on Tuesday morning, according to Hokuriku Electric Power's website. Most areas in the northern Noto peninsula also have no water supply, NHK reported.