The massive slide of snow happened around 5am this morning as early morning climbers made their way up Mount Maudit, which translates as "cursed peak", in the Mont Blanc range.
"There are around eight others injured and at least two people missing," added a spokesman, who said that the avalanche had been caused by snow collapsing in July heat.
All of the injured have been evacuated by helicopter to nearby hospitals, as police supported by search dogs continued to look for survivors.
At 4345m, Mont Maudit is one of a range of peaks also including Mont Blanc du Tacul which are hugely popular with climbers in the summer.
The first ever ascent of Mont Maudit was by a British party in 1878.
Despite being popular as a tourist destination with thousands of Britons in both the winter and summer, the Mont Blanc range is one of the most lethal in the world.
It has killed more climbers than any other mountain range, with the annual death toll regularly reaching beyond the 100 mark.
Many lose their lives as they attempt to scale its peaks with insufficient training or supplies.
