Swiss authorities say "a large number of young people" are among the casualties from a fire at the Crans-Montana ski resort, as work continues to identify dozens of bodies.
Police estimated about 40 people were killed and 115 sustained injuries when Le Constellation bar was engulfed in flames about 1:30am, local time, on January 1, although the exact death toll remains unknown.
Federal minister Chris Bowen said one Australian had been injured in the blaze.
"I can confirm that one Australian has been injured and is receiving medical care and the family is receiving support, Australian consular support," Mr Bowen told Radio National Breakfast.
"It's clearly a terrible, terrible tragedy and I'm sure all Australians send their condolences to the people of Switzerland, the people involved."
Many young people had packed the venue for New Year's Eve celebrations and reports indicate some were trapped while trying to escape via a narrow staircase.
Nathan Huguenin, 19, was at the bar to ring in 2026 and on Thursday said he was "still in shock".
"I feel like it's actually a nightmare, that I'm going to wake up," he said.
"And last night, I didn't sleep a second. I couldn't. I closed my eyes, and everything kept coming back to me because I saw people being resuscitated. I saw people completely burned. I saw people dying."
Another reveller who was at Le Constellation, Axel Clavier, said he was inside the bar when the fire broke out.
"We were trapped. A lot of people were trapped," he said.
"We couldn't see because of the smoke.
"We didn't know how we were going to get out. I was alone and didn't know how I could do it, but I managed to break a window and get out through the window.
"Half of my clothes were gone, it was crazy."
Witnesses have told European media outlets people were waving sparklers close to the bar's wooden ceiling at the time the fire broke out, although officials are yet to confirm how the blaze began.
Two women who survived the fire told France's BFMTV network some of the sparklers were attached to champagne bottles.
Swiss authorities on Thursday said the bar was engulfed after a "flashover", which occurs when all combustible materials in an enclosed room ignite at the same time.
Footage filmed at the scene showed an inferno on the bar's ceiling. While at least one explosion was heard during the blaze, authorities say it was not a terror attack.
Crans-Montana's world-renowned slopes, luxury shopping and high-end restaurants attracts scores of wealthy foreign tourists during the ski season.
Philipp Simmen, from Switzerland's air-rescue service, said survivors with burns were being transferred between hospitals and specialised clinics on Thursday.
"It became clear that there were also a large number of young patients among them," he told Swiss broadcaster SRF.
The most serious cases among the injured were taken to Lausanne University Hospital, about 90 minutes' drive away. They've taken 22 patients so far.
A representative from the hospital told Swiss newspaper 24 heures most of them were aged between 16 and 26.
In Switzerland, it is generally legal for 16-year-olds to enter bars and buy and consume beer and wine, although the legal drinking age for spirits is 18.
Swiss President Guy Parmelin said the fire was "one of the worst tragedies our country has ever experienced" and that "many lives, young for the most part, have been lost".
Crans-Montana is less than 100 kilometres by road from Switzerland's borders with France and Italy.
Rome's ambassador to Switzerland, Gian Lorenzo Cornado, told the country's Ansa news agency that identifying the dead "will take time".
"Unfortunately, many victims are unidentifiable due to the severity of their burns," he said.
Sixteen Italians are missing after the fire, while 12 more were taken to hospital with injuries, the country's foreign minister has said.
