A Frenchman whose job was to check the safety of ski slopes has died overnight after being injured in an avalanche at a popular Alps ski resort, Swiss police said.

The 34-year-old man was one of four injured people rescued after being swept away on Tuesday by an avalanche that hit a slope on Plaine Morte, a glacier near the town of Crans-Montana.

Police in Valais also said that an overnight search did not result in any more people being found.

Rescue crews work on the avalanche site in the ski resort of Crans-Montana, Switzerland
Rescue crews at the avalanche site in Crans-Montana (Jean-Christophe Bott/Keystone via AP)

They said they continued searching all night but stopped on Wednesday morning.

Police said they will resume their search if required.

Nearly 250 rescue workers, medics, police officers and military personnel took part in the search, backed by eight helicopters and a dozen search dogs.