Heavy snow that has blanketed northern Japan for weeks, triggering avalanches and affecting transport networks, has left at least 55 people dead, officials said Thursday.

In one of the country's coldest winters in recent years, 43 people have died as they removed snow from roofs or roads, while seven more were crushed by heavy loads of snow falling from buildings or other structures, the disaster management agency said.

Four people have died in avalanches, with the latest snow slide reported in northern Akita prefecture at a popular mountain resort known for therapeutic hot-spring baths, which left three holidaymakers dead.

The 40-metre-wide (130 feet) avalanche crushed three tents near a naturally heated rock site Wednesday.

Local police and rescuers continued their search Thursday "to confirm there are no others buried in the snow", a local police spokeswoman said.

The extreme weather, which has filled evening news reports for weeks, has also claimed one other life, the government agency said.

Heavy snow has covered the northernmost island of Hokkaido and much of the north of the main Japanese island of Honshu, particularly affecting the country's eastern side.

In Sukayu, in northern Aomori prefecture, where the temperature went down as low as minus 9.2 degrees Celsius (15.4 degrees Fahrenheit) on Thursday, 4.29 metres (14 feet) of snow is lying.

Yamagata and Niigata prefectures have more than three metres of snow, the weather agency said.

Atrocious conditions have led to the cancellation of flights and numerous train delays, including to parts of the shinkansen bullet train system.

In Aomori prefecture, a heavy snowstorm on Wednesday night stranded more than 100 cars on one road, forcing 250 people to seek shelter for the night in local schools, reports said.