TOKYO (AFP) - Up to 11 people are now reported to have died in a winter snowstorm gripping much of Japan, as forecasters warned bad weather would continue.

Northern and central parts of Japan have been lashed by strong winds that have dumped huge quantities of snow over the last few days.

This has disrupted travel and cut off isolated communities.

The Yomiuri Shimbun newspaper said 11 people were known to have died, including a 79- year-old man and a 29-year-old firefighter, who fell into ditches while clearing snow.

Several others, mainly elderly people, have been killed on the northernmost main island of Hokkaido and in regions near the Sea of Japan (East Sea) in mainland Honshu, reports and officials have said.

There have also been deaths on the roads, with hazardous driving conditions provoking hundreds of accidents that have left dozens injured nationwide.

Public transport networks have also been hit, with several hundred flights grounded, most of them domestic, and bullet trains suffering delays.

More than 270 people were stranded in mountainous areas of Niigata and Nagano after the only road linking them with the outside world was blocked by an avalanche, reports said.

The Japan Meteorological Agency (JMA) was warning of the risk of further avalanches across much of the country.

Strong winds gusting at up to 140kmh have also caused tidal surges, and people in coastal areas were being warned of the danger of high waves.

The storm, which was caused by a powerful area of low pressure, "has now peaked but snow is continuing in regions by the Sea of Japan", the JMA said.

More than 200cm of snow was already lying in some areas, with more forecast.