Phurba Tashi Sherpa, the most accomplished high-altitude climber in history, holds a bucket and crowbar as he claws through the rubble of his home seven months after Nepal's earthquake shattered the country.

Despite years of guiding wealthy foreign clients up Mount Everest, something he has done 21 times — a joint record — the 44-year-old has been left penniless.

Phurba Tashi's predicament is shared by many Sherpas, whose homes, lodges and restaurants were destroyed in the April disaster and who complain of a slow response from the government despite billions of dollars of Western aid.

Some retired guides must return to the peaks to earn money. Others are pulling their children out of schools in Kathmandu and hotel-owners are firing staff.

"Everything I worked for was destroyed in a minute," said Phurba Tashi, standing in his village of Khumjung, a cluster of 80 stone houses perched on a plateau surrounded by breathtaking 7,000-metre mountains.

The earthquake that killed almost 9,000 people destroyed his eight-bedroom trekking lodge, badly damaged his house and caused a deadly avalanche around 14 km away on the world's tallest peak.

The remote villages under Everest, which prospered in recent decades thanks to the booming climbing business, suffered some of the heaviest destruction in Nepal's deadliest disaster.

Bookings to scale the world's tallest mountain in 2016 have been a third to half lower than previous years, according to interviews with 18 of the largest climbing firms.

This would be the biggest drop since commercial climbing began on Everest in the early 1990s, and could leave hundreds of struggling Sherpas without work.

An economic blockade of Nepal's border with India could disrupt expeditions and deter would-be climbers, who typically pay a non-refundable fee of $35,000-100,000 for a chance to scale the peak.

Nepal has been facing an acute fuel crisis for three months since protesters in the lowland south, angered that a new constitution fails to reflect their interests, prevented supply trucks from entering from India.

This is crippling the landlocked Himalayan nation as it tries to recover from the earthquake that displaced millions in the central and eastern regions.

Mountaineering firms say the blockade threatens the climbing season because there may be a shortage of fuel to airlift equipment, operate emergency rescue flights or provide enough cooking gas cylinders to survive for two months on the mountain.

"It is a crisis at the moment. It is going to be a catastrophe if this embargo continues," said Phil Crampton, the owner of the New York-based Altitude Junkies.