Japan battles to find New Year's Day quake survivors

Rescue teams in Japan on Tuesday struggled to reach isolated areas hit by a powerful earthquake on New Year's Day, with reports of more than 20 people dead in a disaster that toppled buildings and knocked out power to thousands of homes.

The quake with a preliminary magnitude of 7.6 struck in the middle of the afternoon on Monday, prompting residents in some coastal areas to flee to higher ground as tsunami waves hit Japan's west coast, sweeping some cars and houses into the sea.

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

However, rescue efforts have been hindered by badly damaged and blocked roads and authorities say they are finding it difficult to assess the full extent of the damage.

Many rail services, ferries and flights into the area have been suspended, and one of the region's airports has been forced to close due to cracks in the runway.

"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.

Citing local authorities, Kyodo news agency reported more than 20 deaths from the quake. Public broadcaster NHK said 15 had died just in the hard-hit town of Wajima near the epicentre, where there were also 14 cases of people trapped in collapsed buildings.

Japan's disaster management agency said it had received unconfirmed reports of 19 deaths earlier on Tuesday but official updates on the toll have been infrequent.

More than 140 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 hit in the coming days.

President Joe Biden said in a statement the United States was ready to provide any necessary help to Japan after the earthquake.

"As close allies, the United States and Japan share a deep bond of friendship that unites our people. Our thoughts are with the Japanese people during this difficult time," he said.

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

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

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

The Imperial Household Agency said it would cancel Emperor Naruhito and Empress Masako's slated New Year appearance on Tuesday following the disaster. Kishida postponed his New Year visit to Ise Shrine scheduled for Thursday.