KATHMANDU (AFP) - - The main climbing season on Mount Everest gets under way this month, but China's Olympic torch relay and bad weather could keep scores of big-spending mountaineers from getting anywhere near the summit.

The upper reaches of the world's highest mountain have been sealed off to private expeditions as China attempts to take the Olympic flame to the summit -- in theory before Saturday.

But poor weather appears to be holding up the torch's ascent, meaning that everyday climbers waiting on the Nepalese side of the mountain could be left perilously short of time for their own journey into the "death zone."

Ang Tsering Sherpa, the president of the Nepal Mountaineering Association, told AFP that if the Chinese torch climb drags on after Saturday, other climbers "will not have enough time to get to the top."

"If you look at the records, expeditions usually summit between the 17th and 25th of May. It's going to be tight," he explained.

The spring season offers a brief window for attempts to scale the 8,848-metre (29,198-foot) peak, as jetstream winds at the summit drop briefly before the summer monsoon rolls in at the end of May.

Climbers usually wait for that window at base camp, and make short climbs to acclimatise and pre-position supplies such as tents, oxygen cylinders and gas to melt snow. But for now, they are forbidden from going above 6,500 metres.

China demanded that Nepal impose the restrictions to prevent the kind of protests that have dogged the flame's journey around the globe. On the Chinese side of the peak, private expeditions have been banned altogether.

Many groups used the relay to highlight a range of controversies swirling around China, including its rule of Tibet, alliance with Sudan's government and human rights record.

Sherpa said the uncertainty could be hugely damaging for Nepal as it struggles to emerge from a decade of civil war and political turmoil, and reassert itself as the world's ultimate mountaineering playground.

"If the ban is extended after May 10, it will have a huge impact on tourism," he said.

In all, 32 expeditions of between seven and 12 members each are hoping to tackle Everest this month. Some climbers have paid up to 70,000 dollars for their trip, and such cash is crucial for one of the world's poorest countries.

"The expeditions have already spent so much money, time and energy. If there is not enough time to climb, then it will be a huge waste and a tragedy for Nepalese mountaineering," Sherpa said.

Nepalese tourism ministry spokesman Prem Rai said the country can do nothing but wait -- and hope the Chinese torch team will be up and down the mountain as quickly as possible.

"We are depending on the weather and we are hopeful that the Chinese can make a quick summit," he said, hinting Nepal had little choice but to accommodate the demands of its massive northern neighbour and keep the summit off limits even if the Chinese torch expedition lasts well into May.

Nepal has already deployed troops on the mountain, and confiscated all satellite phones from base camp until the Chinese summit attempt is finished.

Climbers at base camp have been told they will have their Everest permits revoked if they talk to the media. Last month, an American climber was kicked out of Nepal after police found a pro-Tibet banner in his baggage.

Edmund Hillary and Tenzing Norgay were the first to reach the roof of the world in 1953. Since then the peak has been scaled at least 3,000 times.