A Canberra nurse and firefighter say they are devastated to learn their life's work - a charity-funded health clinic in the Langtang Valley in Nepal - has been crushed and staff likely killed in the earthquake.

ACT firefighter and Queanbeyan resident Geoff Bartram, one of Langtang Valley Health charity's trustees, left on Friday for Nepal to conduct a scoping study to find how best they can help.

Sadly, however, it is likely he will be met with more tragedy.

"The whole village [of Langtang, located to the north of the Kathmandu Valley] has been buried and covered by a huge avalanche from the collapse of part of the side of the mountain above the village at the time of the avalanche," said Virginia Dixon, Langtang Valley Health's other trustee and a Canberra nurse.

Langtang's chief district officer, Uddhav Prasad Bhattarai, said on Sunday that the avalanche engulfed the village, according to a local media report.

"Our project manager, who is in close contact with the surviving community from the Langtang Valley in Kathmandu, said everyone is dead,'' Ms Dixon said.

"All of our staff are also presumed dead. We have lost our community, our staff, our clinic, and everything in it."

Ms Dixon works at the National Capital Private Hospital in Woden and has been travelling to Nepal for 20 years.

"In March 2012 I was trekking in Langtang with my husband and when a lodge owner in Kanjen found out I was a nurse he asked if I could do anything for healthcare in the region," she said.

Ms Dixon then went on to set up the Langtang Valley health clinic, to organise donors to "sponsor" nurses and health workers to ensure skilled staff stay in the rural region.

A joint project with the local community, the clinic services a community so remote that getting there requires an eight-hour drive and then a three- or four-day walk from Kathmandu.

Mr Bartram has been visiting and trekking in Nepal since 1978, and said he was still in shock from the news.

"We believe our nurses and perhaps up to 300 people have died in the valley of Langtang,'' he said.

"It is devastating of course, it is just devastating they are employees and they are employees but they have become our family. It is still quite unbelievable."

Mr Bartram is also involved in the Australian Himalayan Foundation, and in that capacity will visit the Langtang Valley and the Solukhumbu region to deliver aid and find out what else is needed.

"Many people have nothing to start from, they can't just go down to Bunnings and get more," he said.

He will be accompanied by Canberra mountaineer Andrew Lock.

"It's quite dangerous to go in there now, the sides of the valley are narrow and subject to rock fall and landslides,'' Mr Bartram said.

"Our objective is to do a quick assessment of the area to see what damage is there and how their aid is best directed. Then in the near future the plan is to send in a medical camp and treat the injured."

A vigil organised by former aid workers and the Canberra Nepalese community was held at Garema Place on Friday.

As well as the Australian Himalayan Foundation and Langtang Valley health clinic, UNHCR and Oxfam are also accepting donations for victims of the quake.