The sheer lack of people with missing limbs being found under the rubble this week was also telling, he said.
"They're telling me there have been more than 6500 deaths so far in Nepal but there's only been four amputations. That can only mean that you're either pulled out of the rubble dead or you're pulled out alive and nobody can treat you so you bleed to death.
"I've been sent pictures of people with legs completely cut off but because there's no immediate medical treatment, they just don't survive."
The organisation recycles prosthetic limbs and hearing aids from developed countries, including New Zealand, to give to people in their rehabilitation programme at the Hope Disability Centre.
It is currently fundraising to rebuild a "deaf school" in the Gulmi area, which collapsed in the earthquake.
A large number of people in the area were now homeless after 500 houses came down, Mr Buchanan said.
"They're all a bit shaken up, telling me there's a lot of aftershocks coming through. We've had about 30 or 40 people sleeping in our centre each night," he said.
Sir Edmund Hillary's son Peter Hillary was just south of Mount Everest base camp when the avalanche hit and has since described his experience as "terrifying".
He had been hiking with a group of friends, one of whom died from a suspected heart attack after the quake, TV3 reported tonight.
"[The avalanche] just swooped over us, covering everything in a blanket of snow and ice. It was terrifying," Mr Hillary said.
One New Zealander who was feared missing has been found but two more are still unaccounted for.
Doug Erin Sealy, 31, from Wellington, was feared to have been in Nepal when the 7.8 magnitude earthquake hit the region on April 25.
Mr Sealy's mother Marie Grant was told today by the Ministry of Foreign Affairs and Trade (Mfat) her son crossed the border into India on April 26.
Ms Grant said Mfat had been "great" and kept in contact with her daily with the latest updates.
Peter Joseph Curreen, 63, from Marlborough, and Peter Donald McLeod, 62, from Taupo, are still believed to be unaccounted for but Mfat said it "does not hold grave concerns" for the missing men.
"We have now confirmed the wellbeing of around 260 New Zealanders in Nepal with only a few New Zealanders unaccounted for," a ministry spokesman said in a statement.
"Consular staff are actively engaging with local authorities in Nepal and continue to follow up leads including those being provided by families."
Anyone who has concerns about a relative believed missing in Nepal, and who is yet to inform Mfat, is asked to contact 04 439 8000.
The ministry advised against all tourist and other non-essential travel to Nepal.
THE MISSING:
Peter Joseph Curreen, 63, from Marlborough, is thought to have been near Jiri, in the Dolakha District east of Kathmandu, when the earthquake struck. It is believed he was most likely trekking by himself or with a small unorganised group, and had been making his way to join a trek to Everest Base Camp. He has not made contact with his family.
Peter Donald McLeod, 62, from Taupo, was listed as missing on the Red Cross Family Links website earlier this week. His name no longer appears, but it is unclear if he has been found.
TO DONATE:
• World Vision: Nepal Earthquake Appeal visit worldvision.org.nz or 0800 90 5000
• Unicef: Visit unicef.org.nz/nepal or call 0800 243 575
• Oxfam: Visit oxfam.org.nz or call 0800 600 700
• Red Cross: Visit redcross.org.nz or call 0800 RED CROSS (0800 733 276)
• ChildFund New Zealand: Visit childfund.org.nz/Nepal-Earthquake-Appeal or call 0800 808 822
• Caritas Aotearoa New Zealand: Visit caritas.org.nz or call 0900 4 11 11
• New Zealand Nepal Society: Donations can be made to bank account number 01-0142-0053378-00
• Himalayan Trust Rebuild Appeal: Visit givealittle.co.nz/cause/nepalearthquake
• TEAR Fund: Visit tearfund.org.nz or call 0800 800 777
• Save the Children: Visit savethechildren.co.nz or call 0800 167 168
• International Nepal Fellowship: Visit inf.org/earthquake-appeal-new-zealand
• Habitat for Humanity New Zealand: Visit www.habitat.org.nz/donate
• The Leprosy Mission New Zealand: Visit leprosymission.org.nz/nepal or 0800 862 873
• MEND: Visit mend.org.nz
