Investigators set about the painful task on Friday of identifying the burned bodies from a blaze that engulfed a crowded bar and killed around 40 people at a New Year's Eve party in the Swiss ski resort of Crans-Montana.

Emanuele Galeppini, a 16-year-old Italian international golfer who lived in Dubai, was the first victim to be identified publicly.

So severe were the burns suffered by the mostly young crowd of revellers in the Le Constellation bar that Swiss officials said it could take days before they name all those killed in the fire that also injured well over 100 people, many of them seriously.

Parents of missing youths issued pleas for news of their loved ones as foreign embassies scrambled to work out if their nationals were among those caught up in one of the worst tragedies to befall modern Switzerland.

"I have been searching for my son for 30 hours. The wait is unbearable," Laetitia, the mother of missing 16-year-old Arthur, told BFM TV, saying she was desperate to know if he was alive or dead, and where.

"If he's in the hospital, I don't know which hospital he's in. If he's in the morgue, I don't know which morgue he's in. If my son is alive, he's alone in ⁠the hospital, and I can't be by his side."

Authorities have warned that naming the victims or establishing a definitive death toll would take time because many of the bodies were badly burned.

"All this work needs to be done because the information is so terrible and sensitive that nothing can be told to the families unless we are 100 percent sure," said Mathias Reynard, head of government of the canton of Valais.

Experts were using dental and DNA samples to identify the victims, he said.

The Italian Golf Federation, which named the young Italian golfer as a victim, said it "mourns the passing of Emanuele Galeppini, a young athlete who carried with him passion and genuine values".

The bodies of those killed have now all been removed from the bar, a Swiss official told Reuters.

Police were still on site to continue investigations into the cause of the tragedy, which Swiss authorities said they were treating as a fire, not an attack.

Some accounts from survivors and footage broadcast on social media suggested that the ceiling of the bar's basement may have caught fire when sparkling candles got too close.

Axel, who was in the basement where the fire started, told reporters he did not know how he "miraculously" made it out.

He turned over a table and hid behind it to protect himself from the fire, before making his way upstairs.

"We couldn't see anything, I was half choking," he said.

He used a table, and then his feet, to break a window to get out, avoiding what he said was a single door that was too narrow for the many people trying to escape.

Italian Foreign Minister Antonio Tajani, who was in Switzerland, said that only three of those treated in hospital for injuries were yet to be ⁠identified.

He said that 13 Italians were in hospital and six registered as missing.

France's Le Midi Libre newspaper said one French woman had been identified among those killed in the fire. France's foreign ministry declined to comment.

Swiss officials have said around 40 people were killed but Italy has put the death toll at 47, based on information from Swiss authorities.

Several of those seriously injured were receiving care in hospitals in neighbouring countries, including France and Germany.

Visitors and residents of Crans-Montana, which is a popular draw not only for skiers, but also golfers, were stunned by the inferno.

Dozens of people left flowers or lit candles on a makeshift altar at the top of the road leading to the bar which police had cordoned off. Some cried, others quietly hugged one another.

"It could have been us," Emma, an 18-year-old from Geneva, said outside the cordoned-off bar.

"There was an enormous queue so we decided not to go in," she said. "I see those missing and it's all people our age."

Elisa Sousa, 17, said she was meant to be there but ended up spending the evening at a family gathering instead.

"And honestly, I'll need to thank my mother 100 times for not letting me go," ⁠she said at the vigil for the victims. "Because God knows where I'd be now." (Reuters)