Australian tunnelling expert Arnold Dix says Nepali authorities have found fresh air for the first time in the tunnels filled with mud and debris in last month's floods.
A suspected 900 people have been trapped in the tunnels of hydropower projects in Nepal since the August 26 floods buried the tunnels' entrances and cut off those inside.
What's next?
Nepal's Prime Minister Balendra Shah has vowed there would be no let-up in the rescue operations.
Nepali authorities have found fresh air for the first time in the tunnels filled with mud and debris in last month's floods, an Australian tunnelling expert says.
At least 11 hydropower projects were engulfed when a glacier collapsed into a river on the Nepal-China border on August 26, burying the entrances to the tunnels of the projects under debris and mud and trapping those inside.
Melbourne geologist Arnold Dix was invited to Nepal to work with rescue teams at the Chilime hydropower project in the hard-hit Rasuwa district.
"We think we've found a zone where people may have survived and that is just amazing," he said.
"This is the first time we've had fresh air, as opposed to water and mud.
"We can hear that it's hollow, we're calling out. It's not over.
The person is the eighth Australian to be found since the floods, with 35 others still unaccounted-for.
Professor Dix said people trapped in the hydropower project tunnels have had to survive in pitch black for over two weeks, with only access to water.
"What you do is listen to your heart, you do your engineering analysis, and you go after those souls that we think could still be alive,"
he said.
The geologist, who also assisted rescue teams at the Trishuli 3A hydropower project, previously told the ABC people could survive in the tunnels for up to 17 days.
He said last week that some of the underground power stations likely withstood the immense pressure of the flash flooding. However, it remains unclear whether emergency systems activated in time or whether water and debris inundated them.
In recent days, search teams have rescued four people, including a Chinese national who was pulled from a tunnel on Saturday.
The others were two hydropower workers rescued from another tunnel on Friday and a Nepali woman pulled out from her buried house on Saturday.
Nepal's Prime Minister Balendra Shah vowed there would be no let-up in the rescue operations.
"We know our responsibility and its sensitivity. We are translating the humanitarian spirit of the Nepali people into practice through the search and rescue operation," he said in a social media post late on Monday.