Around 800 deaths have been reported and at least 3000 people are still missing after the disaster, triggered by a glacier collapse in the Himalayas near the Nepal-China border on Wednesday.
Australia has sent 12 response team personnel and pledged millions in aid, including hygiene kits and solar lights to be delivered by the defence force later in the week.
Among the Australians still missing are four members of the Isaah Yeo family, Sreedharan, Lakshmi and their sons, Rudra and Rishabh.
Rishabh's partner, Sarada Vishwanathan, said the family are upset, disappointed and very scared.
"The main thing we want now is to try and get the Australian government to go over there, send their troops over to find our people," Ms Vishwanathan told Nine's Today program.
"It's been five days now, and we know that the critical window of survival is getting slimmer and slimmer as the days pass. And we just have no answers.
With Nepal a "third world country" lacking critical support, "we need to send our Australians there to try and find our family", she said.
Ms Vishwanathan's partner and family were visiting the area for a religious pilgramage in Mount Kailash in Nepal, but had not been seen or heard since Wednesday morning.
"Which has been most hard hit by these Nepal floods and we know that those areas have been cut off by all communication," she said.
"But we've heard reports that maybe they could have run up the hill. Maybe they could have fled. We know that it's a very mountainous and forested area, but we still have hope. We have hope every single day that they're up there somewhere, but they just can't reach us."
Assistant Foreign Affairs Minister Matt Thistlethwaite on Monday confirmed the number of Australian's unaccounted for in the disaster had risen to 43 overnight.
"Our embassy staff in Kathmandu are working around the clock, and we've actually sent an additional 12 personnel to Kathmandu to assist yesterday our ambassador," Mr Thistlethwaite told ABC's Radio National.
"We remain hopeful of rescuing and returning them safely."
He said while the Chinese government had refused an offer for assistance from Australia, the Nepalese government had requested additional support, which includes an additional $3 million, taking the total support package to $8 million.
Most of that support is in the form of hygiene kits and solar lights.
On top of that, Australians have raised millions of dollars to assist survivors, with many forced into temporary shelters amid mud and chaos.
The survivors remain in desperate need of basic amenities like clean drinking water and medical supplies.
Among them, Rabindra Hamal told AAP he and his colleagues working at a dam site were told to flee just minutes before the flood hit their area on Wednesday.
They made their escape by car, but as they later tried to reach higher ground by foot, two of the group were swept away.
"It was completely terrifying," he said. "We couldn't believe it."
The group continued to scramble to safety but were forced to wait until the following day to be rescued.
They flown by helicopter to a nearby army barracks and then evacuated to Kathmandu.
Mr Hamal said of the several thousand people who were working on the hydro project, about 500 people were still missing.
A public candlelight vigil will be held at Melbourne's Federation Square on Monday evening, in memory of those lost in the disaster.
