At least six people died in a spate of snow-related incidents as blizzards swept across the northern Japanese island of Hokkaido over the weekend, police and news reports said Sunday.

A 40-year-old woman and her three teenaged children were found dead late Saturday in a car buried under snow in the town of Nakashibetsu, eastern Hokkaido, a local police spokesman said.

They are believed to have died of carbon monoxide poisoning as the car's exhaust pipe and was blocked by snow and the windows were up, Kyodo News said, adding that snowfalls of more than two metres (6.6 feet) were recorded in the area.

A 23-year-old woman who went missing in the same town was found dead on Sunday in snow some 300 metres away from her car, Jiji Press news agency said.

In Yubetsu, northwest of Nakashibetsu, a 53-year-old man was found dead on Sunday after he and his nine-year-old daughter became buried in snow on farmland, Jiji reported.

The two went missing after leaving their home Saturday in a truck. They were found outside in the snow and it appeared the father had placed his body over his daughter's, Jiji reported.

He was pronounced dead in hospital, while the girl was found to have no life-threatening injuries.

Japan's meteorological agency issued a warning of strong winds and heavy snow in northern Japan, with gusts of up to 135 kilometres (84 miles) per hour recorded in Erimo cape, southern Hokkaido, on Saturday.