The crash happened on the Kan-etsu Expressway in Minakami, Gunma prefecture, about 160km (100 miles) north-west of Tokyo, at about 19:30 local time (10:30 GMT) on 26 December.

It took about seven and a half hours to put out the fire, police said.

Following the incident, a section of the highway was closed, with a long line of vehicles, many charred beyond recognition, stuck in the outbound lane. Work is under way to tow them away.

A man in his 60s, whose vehicle was involved in the accident, told local media outlet NHK he heard a loud explosion from the far end of the pile-up and saw fire during the crash. The blaze then spread to other vehicles, he said.

He said he was evacuated to a nearby toll gate with about 50 other people and spent the night in the hallway there.

Nexco, which operates the road, said checks were needed to see if the surface was damaged by the fire.

The company is warning travellers not to use the highway.