Four people have been killed in an avalanche while skiing down a slope in the Swiss Alps.

The accident happened on Saturday as experts warned of considerable avalanche risk in Switzerland and Austria, where one skier also died under masses of snow.

In Switzerland, a group of nine skiers was at an altitude of 2200 metres on an off-piste tour to peak Vilan near the Austrian border, when the snow swept down the mountain.

Three were found dead in the snow, while rescuers flew four additional skiers with serious injuries to hospitals where one of them died.

As in most of Switzerland, Swiss avalanche experts had declared a "considerable" avalanche risk in the Vilan area, the third highest of the five-level avalanche danger scale.

At this level, avalanches can be easily triggered even by single skiers on a slope.

Fresh snow had fallen prior to the accident, a police spokeswoman said.

Less than a two-hour drive from the accident site, a man was killed in an avalanche while skiing off-piste in the Austrian resort of Damuels.