KATHMANDU: At least 28 people were killed and more than a dozen injured Tuesday after a packed passenger bus plunged off a road in a hilly region in northwestern Nepal, officials said.

The accident in the remote Mugu region happened at around 12.30pm local time (0645 GMT) after a puncture to one of the front tyres, district official Rom Bahadur Mahat told AFP.

The bus was driving from the southern Banke district to the Mugu area and was believed to have been carrying at least 45 people, many travelling to celebrate the Hindu festival of Dashain.

"The accident has killed 28 people, we are trying to identify the bodies. The injured are being treated in hospitals," Mahat added.

Helicopters airlifted the injured to hospitals for treatment, with rescuers continuing to search for survivors and victims at the crash site late Tuesday.

The bus drivers pick up travellers along designated routes but some passengers are not formally registered, making it difficult for officials to know the total number onboard.

Deadly traffic accidents are relatively common in the Himalayan nation due to poor road conditions, badly maintained vehicles and reckless driving.

More than 2,500 people died in nearly 13,000 road accidents in Nepal in 2019, according to government data.