KATHMANDU (AFP) - An environmental group is asking the Nepal government to consider installing portable toilets on Mount Everest for climbers caught short at the roof of the world.

Eco Himal says the thousands of trekkers who set off from the South Base Camp in Nepal each year would do a better job of keeping the place clean if they and their porters had somewhere civilised to go when nature called.

"Human waste is a problem, of course," said the group's director, Phinjo Sherpa. "I am merely suggesting that if we have public toilets they can be used."

Many groups bring expedition toilet cans, but Phinjo Sherpa said porters were often left with little choice but the nearest snowdrift.

Environmental activists say Everest is littered with the detritus of past expeditions, including human waste and mountaineers' corpses, which can take decades to decompose because of the extreme cold.

Phinjo Sherpa said installing the toilets would be discussed as part of a wider waste management plan being prepared by the government that would encompass popular peaks throughout the Everest region.

"If there could be two or three toilets that would be good but this is just at the planning phase. We will have to decide what is a good idea and what isn't," he said.

Climbers spend tens of thousands of dollars trying to reach the 8,848-metre

(29,028-foot) summit of Everest, but campaigners say few pay much attention to the rubbish they leave behind.

There is no definitive figure on how much trash has been left on the mountain, but the debris of 50 years of climbing has given Everest the name of the world's highest dumpster.

The privately-funded Eco Everest Expedition, a Nepal-based coalition of environmentalists campaigning to keep the mountain clean, has collected more than 13 tonnes of garbage, 400 kilogrammes of human waste and four bodies since 2008.