A severe snowstorm sweeping across Japan has killed 19 people and left more than 1,600 injured, media and officials said Monday, as the extreme weather sparked widespread transport chaos.

At least 19 people have died in snow-related incidents after the record-breaking storm, the top-selling Yomiuri Shimbun reported, with the storm now battering the northern island of Hokkaido.

Many of the casualties were involved in car accidents, while others were crushed to death after roofs collapsed.

More than 6,900 people were trapped in small communities cut off by snow-blocked roads and railway lines, the Yomiuri said, while gasoline deliveries to some petrol stations were delayed due to impassable roads.

In Yamanashi prefecture west of Tokyo, stores were facing a serious fresh food shortage, the Yomiuri and public broadcaster NHK reported, with Prime Minister Shinzo Abe promising to send a government team to help the struggling area.

"We will do everything we can to protect the lives and possessions of people in cooperation with local governments and relevant ministries," he told parliament Monday

Toyota, Honda and Suzuki were forced to suspend operations at a total of nine of their factories in central and eastern Japan on Monday due to parts shortage and workers' absence following the heavy snow, company spokesmen said.

Honda said the suspension affected production of some 2,000 cars, while Toyota and Suzuki said the impact was not immediately known.

Toyota said one plant would remain closed until at least Tuesday morning, while Suzuki and Honda have yet to announce their schedule for Tuesday at the closed assembly lines.

The storm is now moving towards northernmost Hokkaido, Japan's meteorological agency said, warning of heavy snow, blizzards and avalanches as well as high waves along the northeastern coast, which was battered by a quake-sparked tsunami almost three years ago.

Despite around-the-clock clearing efforts, hundreds of cars on Monday remained stuck on some mountain roads, leaving drivers stranded, local officials told AFP.

National Route 18 that runs through Gunma and Nagano prefectures north of Tokyo is still partly closed, with cars stuck along several kilometres due to the heavy snow.

Members of Japan's Self-Defense Forces have also stepped in to help.

"Efforts to remove snow from the roads are continuing with Self-Defense Forces servicemen working from 7:00 am this morning," said an official at the Karuizawa ski resort in Nagano prefecture.

The transportation ministry and municipal governments are delivering emergency aid to stranded drivers, officials said.

Snow began falling Friday morning in the capital Tokyo and had piled up to 26 centimetres (10 inches) by early Saturday, a week after the heaviest snowfall in decades left 11 people dead and more than 1,200 injured across the nation.

Most snow in the capital has melted, but forecasters predict more falls in the region around Tokyo later this week.