An overnight tour bus on its way to a ski resort in central Japan has slid down a mountainside, killing at least 14 passengers and injuring 27 others.
Fire and disaster management officials say the bus veered off to the opposite lane on a mountain road near the resort town of Karuizawa, in Nagano prefecture, ramming through a guard rail and sliding down the mountainside.
The bus was carrying 41 people, including two drivers who were taking turns, when it crashed early on Friday.
Most passengers were ski enthusiasts aged 18 into their early 20s, according to the Tokyo-based ski tour operator Keyth Tour.
Packaged ski tours that come with overnight bus rides, lodging and lift tickets for around Y12,000 ($A145) are very popular among university students.
Japanese media reports say the bus fell three metres down the mountainside and landed on its side, with its front window bashed in.
There was no snow or ice on the road surface.
The injured were being treated at nearby hospitals. The Fire and Disaster Management Agency said 13 of the 27 passengers were seriously injured.
A male survivor, identified only as a student, told broadcaster NHK that the bus swayed significantly before falling off the road, and he was stuck in a small corner when the bus finally came to a stop.
“I desperately tried to get out and struggled, and the next thing I remember is that I was outside,” he said.
A Department of Foreign Affairs and Trade spokesperson said the Australian Embassy in Tokyo has been in regular contact with Japanese authorities, and at this stage, is not aware of any Australians involved in the bus crash.