Hundreds of foreign tourists stranded by heavy fog in the Everest region are hiking their way to safety across the Himalayas, an official said Sunday.

With continuing bad weather hampering their rescue, up to 400 of the thousands of stranded trekkers have given up waiting for the fog to lift and are heading to Jiri, a four-day walk away, to pick up buses back to Kathmandu.

Managers on Wednesday were forced to close the only airstrip in Lukla, the gateway for climbers heading to Everest and surrounding mountains, grounding all flights in and out of the region.

"There is a very low visibility so we are not expecting the resumption of regular flights today," said Utsab Kharel, the manager of Tenzing Hillary Airport in Lukla.

"Around 300 to 400 tourists have walked from Lukla to Jiri after losing hope of an improvement in the weather."

The army had hoped to deploy its rescue helicopter, which carries up to 40 people, but bad weather has prevented it from accessing Lukla, 135 kilometres (84 miles) from Kathmandu.

"Small helicopters have continued rescuing tourists from Surke, a village a one-and-half hour walk from Lukla," said Kharel. "They have carried around 400 foreigners to Kathmandu."

The stranded trekkers, including Americans, Britons and Germans, have been sleeping at the airport and in tents and dining halls at Lukla hotels, officials say, with the fog not expected to lift until at least Monday.

"Still 300 tourists are in Surke waiting their turn. Around 2,200 to 2,500 are languishing in Lukla," Kharel said. "The prices of daily commodities have soared up and the stock of meat and vegetables is running empty."

Nepal, a popular destination for mountaineers and trekkers, has eight of the world's 14 tallest peaks over 8,000 metres, including the world's highest, Mount Everest, at 8,848 metres (29,029 feet).

Thousands of foreign tourists visit the Everest region during the peak tourism season late in the year.

Around 500 travellers fly in and out of Lukla on a normal day when weather conditions are good.