The protective layer covers an area of 2,500 square metres (26,910 square feet) of the Gurschen glacier at Andermatt in the centre of the country, Andermatt Gotthard Sportbahnen SA which operates ski lifts said.

The initiative has been criticised by environmentalist groups which say it serves no purpose.

The sheet covering the glacier, situated in the canton of Uri, is 3.8 mm (0.15 inch) thick and made of synthetic fibres which protect the snow cover from ultraviolet radiation with the aim of preventing the ice from melting.

It will be removed in the autumn and put back next spring.

Over the past 15 years the glacier has receded by about 20 metres from one of its stations, the ski lift company said.

But the WWF environmental group said that "covering up glaciers is not going to solve the problem of global warming."

Only climate protection measures such as cutting back greenhouse gases are useful, it said in a statement.

Eight activists from the Greenpeace environmental group unfolded banners on the glacier overnight, calling for the protection of the climate rather than treatment of symptoms.

The Pro Natura group attacked the ski lift company for extending its car parks near the lifts, saying ski resorts should improve access by public transport.

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