A woman airlifted from an earthquake-affected area is carried on a stretcher in Nepalgunj, Nepal, on Saturday. AP

Rescue workers in Nepal began digging through the rubble of collapsed houses with their bare hands on Saturday, searching for survivors after the country's worst earthquake in eight years killed 157 people and shook buildings as far away as New Delhi.

In a statement carried by Reuters, Nepal's National Seismological Centre said the quake struck the Jajarkot region in the west of the Himalayan nation at 23:47 GMT on Friday with a 6.4 magnitude. The German Research Centre for Geosciences measured it at 5.7 and the US Geological Survey at 5.6.

Officials fear the death toll could rise as first responders had reached the hilly area near the epicentre, some 500km west of the capital Kathmandu, only early on Saturday and began searching for survivors.

"The number of injured could be in the hundreds and the deaths could go up as well," Jajarkot district official Harish Chandra Sharma told Reuters by phone.

Although the quake's magnitude was not severe, the damage and the death toll are high due to the poor quality of construction in the area and because it struck while people slept, officials said.

Mud houses were flattened or damaged as survivors crouched outside for safety, the sirens of emergency vehicles wailing.

The quake was felt as far away as India's capital New Delhi, nearly 500 km from the epicentre, 42 km south of Jumla.

"Ninety-two people died in Jajarkot and 40 in Rukum," home ministry spokesman Narayan Prasad Bhattarai told the media, referring to the two districts hit worst by the quake.

This screen grab from video shows villagers stand in front of their damaged houses from earthquake in Jagarkot. AP

National police spokesman Kuber Kathayat said that authorities had tallied more than 100 others injured across both districts.

Security forces have been deployed to assist with search and rescue operations, Karnali Province police spokesman Gopal Chandra Bhattarai told AFP.

"The remoteness of the districts makes it difficult for information to get through," he added.

"Some roads had been blocked by damage, but we are trying to reach the area through alternate routes."

A doctor looks after a patient injured in an earthquake in Nepalgunj, Nepal, on Saturday. AP

The district hospital was packed with residents bringing in injured victims.

‘Human and physical damages’

Nepalese Prime Minister Pushpa Kamal Dahal arrived at the site of the quake on Saturday after expressing "his deep sorrow over the human and physical damage caused by the earthquake".

In neighbouring India, Prime Minister Narendra Modi said he was "deeply saddened" by the loss of lives.

"India stands in solidarity with the people of Nepal and is ready to extend all possible assistance," he added.

People airlifted from an earthquake-affected area arrive in Nepalgunj, Nepal, on Saturday. AP

Nepal lies on a major geological faultline where the Indian tectonic plate pushes up into the Eurasian plate, forming the Himalayas, and earthquakes are a regular occurrence.

Nearly 9,000 people died and more than 22,000 were injured in 2015 when a 7.8-magnitude quake struck Nepal, destroying more than half a million homes.

It damaged or destroyed nearly 8,000 schools, leaving almost one million children without classrooms.

Hundreds of monuments and royal palaces -- including the Kathmandu Valley's UNESCO World Heritage sites -- that had drawn visitors from around the world were destroyed, in a major blow to tourism.

A motorcycle is seen in the midst of the rubble in the aftermath of an earthquake in Jajarkot. AFP

Six people died in November last year when a 5.6-magnitude earthquake struck Doti district, near Jajarkot.

Indian social media users reported feeling Friday's quake in the northern cities of Lucknow and Patna.

It was followed several hours later by an aftershock in the same area with a 4.0 magnitude, USGS said.

Agencies