This is the moment thick smoke from mountain fires shrouded homes in Uenohara, Japan.

Footage captured by Haruno Suke from an Azusa express train shows fumes billowing over Mount Ogi, which has been engulfed by fire for a week.

Local media reported that the blaze had burnt 162 hectares of forest by Thursday, January 8.

Kenji Uematsu, a section chief at the Okayama City Fire Department, said: 'The fire was caused by a bonfire. The flames spread while pruning debris was being burnt in an open space.'

Fire crews are using helicopters, water hoses, and backpack water tanks to stop the blaze. However, the fire is still not under control.

Authorities have issued a dry-air warning, and very little rain is expected in the area over the next week.

While 145 residents were evacuated in Uenohara, officials confirmed that no one has been injured and no buildings have been damaged so far.

Last year, a forest fire in Okayama City burnt 486 hectares and destroyed 19 buildings, making it the largest fire in the city's history.

Fire officials recorded that roughly 65 per cent of forest fires over the last 10 years were started by bonfires.

Authorities are now urging the public to be extremely careful and to put out fires properly after use.