Rescuers on Sunday ruled out finding any more survivors of a landslide in northeast Nepal that is feared to have buried dozens of people under tonnes of mud and rocks.

Eight bodies have been pulled from the rubble after the landslide struck hamlets along a river in Sindhupalchok district before dawn on Saturday burying homes and leaving at least 100 people missing.

"It has been over 24 hours that people would have been buried in mud. We have no hope of finding anyone alive," government disaster management head Yadav Prasad Koirala told AFP in Kathmandu.

As police and soldiers resumed their search for the missing, efforts were also underway to clear landslide debris blocking the Sunkoshi river, sparking fears of flash floods downstream, including across the border in India.

The debris has dammed the Sunkoshi which also runs into India's eastern state of Bihar as the Kosi river.

Authorities in Bihar have evacuated more than 20,000 people amid fears that a torrent of water could inundate villages and farms if the dam suddenly breaks, officials said.

"So far 20,000 people have been evacuated and they have reached at different relief camps set up by the government," Vyas Ji, principal secretary of Bihar's disaster management department, told AFP.

"We have information that their number is increasing and it may have crossed 25,000 now," he added.

Disaster response teams have been deployed to vulnerable areas of Bihar, while the army was on stand by, the state government said.

The Kosi river burst its banks in 2008 and shifted away from its normal course, engulfing swathes of Bihar and killing hundreds of people.


'100-150 people still missing'

Nepalese workers on Saturday carried out small explosions to clear the debris and break open the dam which has created a large 110-metre (360-feet) deep lake in the river.

At least two hydropower stations have been flooded at the site, forcing them to shut down. A three-kilometre stretch of the Arniko Highway, which connects Nepal with Tibet in China, has also been submerged and been closed.

Officials have opened a barrage on the river near the India-Nepal border to allow more water to flow downstream and reduce the risk of flooding, Nepal's Koirala said.

"The water is gradually clearing out, the artificial lake created due to the blockage is shrinking, so the danger is lessening," he said.

Rescuers on Saturday airlifted 34 people to safety from the landslide site, including 19 who suffered serious injuries.

A lack of official records has made it difficult for rescuers to determine how many people were in the hamlets when the landslide caused by monsoon rains hit.

"We are trying to find out who lived where from eyewitnesses and from relatives. We estimate 100-150 people are still missing," Koirala said.

Scores of people die every year from flooding and landslides during Nepal's monsoon season.

Nepal's landslide came as more than 150 people were feared dead in neighbouring India following a landslide which destroyed a village in western Maharashtra state on Wednesday.