A glacier collapse on Wednesday unleashed a huge torrent of rock, ice, mud and debris through Himalayan mountain river systems, killing at least 579 people in Nepal and five in China's Tibet.
The number missing in Nepal has nearly doubled to 1924, the country's disaster authority said on Friday, in a figure that includes 38 Australians.
At least 558 were missing in Tibet's Gyirong County, including 260 foreigners, Chinese state broadcaster CCTV said on Thursday.
More than 90,000 people are estimated to have been affected by the disaster, the Red Cross said.
The flooding led to the formation of a lake, which on Friday began overflowing into the Lhende Khola and Trishuli rivers.
The overflow sparked panic and warnings from authorities in Nepal, leading to rescue operations being suspended for about three hours.
The risk prompted all Chinese rescue personnel and vehicles to withdraw as well, CCTV said.
Both resumed rescue operations after the threat eased, with Nepali officials saying that they were still hopeful of finding survivors.
Dramatic footage emerged of a spectacular rescue in Nepal, where the army pulled two mud-covered workers out alive from a tunnel at a hydropower plant.
The men were carried on people's backs to a helicopter, as a video showed.
Nepal is continuing to monitor two barrier lakes upstream of the flood zone, with an official warning that flood risks will persist until both lakes fully drain.
Satellite imagery showed the second lake growing larger with no visible outlet, raising concerns that water pressure could still be building.
China's state-run Xinhua news agency said that the first barrier lake was reducing in size, citing analysis by the water resources ministry.
A Chinese government geohazards expert warned, however, that the lake may be unstable and that more than 100 glacial lakes scattered throughout the area could pose a threat.
Wednesday's flood ripped through villages and valleys, destroying power stations, roads and bridges along a route that links Kathmandu with Lhasa in Tibet and is popular with trekkers and pilgrims.
Of those missing, at least 540 are foreigners, many of them Hindu pilgrims from India headed to the holy Mount Kailash and Lake Mansarovar in Tibet.
Ten bodies were found in three places in the northern Indian state of Uttar Pradesh in rivers that flow down from Nepal, police told Reuters on Friday.
In Beijing, a Politburo meeting chaired by President Xi Jinping called for stronger monitoring of glacier lakes and landslide risks, and for closer international disaster co-operation, Xinhua reported.
China's Premier Li Qiang, the country's No. 2 official, arrived in the disaster-stricken area of Gyirong on Thursday afternoon, Xinhua said.
Chinese rescuers had yet to reach the worst-hit site on the Chinese side of the border, the Gyirong border crossing, by Thursday evening, state media reports indicated, as crews worked to clear a key access road.
Footage on Wednesday showed torrents of water and debris tearing through the border crossing, engulfing people trying to flee.
Earlier, Nepalese rescue teams used helicopters to search for survivors and drop emergency supplies to thousands cut off in towns and valleys while emergency services recovered dozens of bodies swept down into the plains.
Dibga Tamang was among the last people rescued from Rasuwa on Thursday, airlifted along with three others to an army camp in Nuwakot.
"All of our people have gone. They are dead," Tamang said.
"I have no one left waiting for me. Everything and everyone is gone. The end."
A large number of people arrived at an army base in the area seeking information about missing and dead family members.
Bodies were brought into the barracks and lists of rescued people were posted outside.
Around the world, relatives of those missing were desperate for information.
with DPA
