Nepali families held symbolic funerals on Wednesday (Sep 2) to "liberate the souls" of relatives missing since deadly flash floods swept away their villages and homes in the Himalayan region a week ago.

Emergency teams have recovered more than 1,100 bodies, and nearly 4,500 people are missing after the gigantic wave of freezing water, rocks and debris triggered by a high-altitude glacial collapse roared down the China-Nepal border on Aug 26.

After days of searching shelters and mortuaries, relatives of some of the missing lost hope and began conducting last rites, burning straw effigies in Hindu rituals.

"We had to do this to set his soul free, so that he is at peace and happy wherever he is," said Dolma Newar Tamang, flanked by her sobbing son, at a funeral for her husband.

He had been en route to China when the disaster struck.

"I saw the news and called him," she told AFP. "I called repeatedly, but he never picked up."

A week on from the colossal disaster, Nepali rescuers are still seeking survivors, including by digging through packed sludge that has entombed multiple tunnels of hydropower plants.

So far, rescuers have recovered only bodies from tunnels, but teams were still digging, drilling and blasting through debris.

Nepal's Foreign Minister Shisir Khanal said he still hoped some missing people could be alive.

"Miracles do happen," he told AFP. "At this point, I do not want to completely give up hope."