The environmental group Greenpeace, which commissioned the photoshoot by photographer Spencer Tunick, said the volunteers turned up under blue skies near the foot of the Aletsch glacier, a protected UNESCO World Heritage site.
"Their numbers are close to 600," Nicolas de Roten of Greenpeace Switzerland said.
“It's relatively chilly but that doesn't seem to be disturbing them," he added.
The campaign is aimed at drawing attention to melting Alpine glaciers, one clear sign of global warming and of man-made climate change, according to the group.
Greenpeace says the human body is as vulnerable as glaciers like the Aletsch in southern Switzerland and the world's environment.
The glacier itself is now shrinking by about 100 metres a year.
The group hopes its billboard and poster campaign showing people exposed to the cold will send a shiver down the spines of public opinion and politicians, and convince them to do more to tackle pollution and climate change.
"They'll be used at the right moment for our campaign, in Switzerland first and then worldwide," de Roten said from the location, about an hour's hike from the village of Bettmeralp.
Tunick split the men and women into two groups of about 300 for separate shots on or around the lower end of the spectacular 23 kilometre long sweeping ice floe, at an altitude of about 2,300 metres.
Dressed in hiking gear, they stripped for minutes at a time, watched at a distance by clump of media photographers and journalists.
If cooler than summer down in the valley, temperatures were well above freezing – about 10 to 15 degrees Celsius – unlike the riskier snowbound section higher up in the mountains.
The US-born photographer is renowned for his spectacular art photos of hundreds if not thousands of naked people grouped in carefully chosen poses around landmarks.
Tunick calls them "living sculptures" or "body landscapes" and he nowadays works mainly to order for contemporary art galleries.
About 18,000 nudes posed for the US-born photographer in Mexico City's Zocalo Square in May.
Other backdrops have included the Gateshead Centre for Contemporary Art in England (2005), the Biennale in Lyon, France (2005), and Grand Central Station in New York (2003).
Volunteers for the Swiss photoshoot were asked to turn up by train and cable car, to avoid generating carbon dioxide emissions that contribute to global warming.
Bettmeralp's mayor, Heidi Kreuzer, was unimpressed by the fuss.
"There's no need to get undressed, I can show you very nice pictures of the glacier," she told the Swiss newspaper Le Matin.
Environmental issues have considerable resonance in mountainous Switzerland, which has been hit by a growing number of damaging flash floods and landslides in recent years due to stronger storms and rainfall, as well as heatwaves.
A Swiss government report this week underlined that temperatures were rising faster than the global average, and measures needed to tackle the impact of global warming would cost the country about one billion Swiss francs ($A1.05 billion) a year.
The country's 1,800 glaciers are regarded as a visible barometer of global warming.
The Aletsch alone shrunk by 114.6 metres in the year in 2005-2006, according to scientists at Zurich's Federal Polytechnic (ETHZ).
Their data also shows that all Switzerland's main glaciers are retreating and the melting has accelerated since the mid-1990s.
Greenpeace wants to to use the campaign during Swiss general elections in October, to press for tougher action to cut emissions than the government's planned carbon tax, de Roten said.