Snow has reached 1.36 metres in Fukui prefecture, 320km west of Tokyo, as of 1600 AEDT on Tuesday, the heaviest snowfall in nearly four decades in the region, a local meteorological observatory said.

The traffic standstill, stretching for about 10km in the prefecture, was caused by some cars going off the shoulder of the road in the snowstorm and others stopping to put on tire chains as a precautionary measure, an official at a local office of the Transport Ministry said.

"We have blocked traffic heading into the affected area, so no more cars will join the jam. In some parts, cars have resumed moving, but only to be caught in a standstill again," the official said.

The snowfall in Fukui is expected to continue at least until Wednesday morning, the local observatory said.