At least 46 people have been killed after a massive landslide trapped two buses and washed away houses in the Himalayan foothills of northern India.

Soldiers and volunteers resumed rescue operations in the Mandi district of the Himachal Pradesh state on Monday, a day after heavy monsoon rains triggered the mudslides.

Soldiers managed to pull the bodies from the buses that were covered with rocks and mud.

Officials said five injured were admitted to the zonal hospital in Mandi town.

READ MORE: Floods, landslides kill scores across Nepal and India

Intermittent rain has been hampering the rescue work, and army personnel had to stop late on Sunday with more rain threatening to cause another landslide, police superintendent Ashok Sharma said.

Two buses, two cars and a motorbike had been trapped on a highway near Kotrupi village by Sunday's landslide, said Mandi district official Sandeep Kadam.

The buses had halted for refreshments at midnight on Saturday when tonnes of rock and mud swept away an entire stretch of highway roughly 200km from the state capital Shimla.

With the road blocked in several places, soldiers used shovels and pickaxes to remove rocks, boulders and debris covering the buses and pull out the bodies.

Earth-moving equipment was brought in later to speed up the clearing operations.

Sharma, who was overseeing the rescue operations, said the death toll could rise and he did not hold out much hope for survivors.

"One of the buses is buried under nearly 15 meters of mud," he said. "It will take us many hours to extricate the bus."

Prime Minister Narendra Modi tweeted his condolences for the victims: "Pained by the loss of lives due to landslide related accidents in (Himachal Pradesh's) Mandi district. My condolences with the families of the deceased."

Pained by the loss of lives due to landslide related accidents in HP’s Mandi district. My condolences with the families of the deceased: PM — PMO India (@PMOIndia) August 13, 2017

Hundreds have died across India in torrential rain, floods and landslides since the onset of the wet season in April.