KATHMANDU (AFP) - Nepal's Prime Minister has pledged to set up a weather warning system after a major Himalayan snowstorm killed 32 people at the height of the trekking season, 17 of them tourists.

Forecasters had predicted the snowstorm, but many walkers appeared to have been caught unawares and were heading to an exposed high mountain pass that forms part of the popular Annapurna Circuit trekking route when it struck.

Mr Keshav Pandey of the Trekking Agencies' Association of Nepal (TAAN) said it was the worst loss of life in a single day for trekkers, guides and porters in the country and called for a better system to warn tourists.

Nepal's Prime Minister Sushil Koirala pledged to provide better weather information in tourist areas, saying the loss of life was "extremely tragic at a time when worldwide weather updates are available every second". "I want to assure that the government will make efforts to establish early warning centres for weather in the important spots across the country, especially in the Himalayan areas and along rivers," he said in a statement on Thursday.

On Friday, emergency workers on foot and in helicopters resumed their search for survivors, rescuing seven more people, including two tourists, a day after they airlifted more than 150 to safety, officials said.

They also recovered the body of a Nepalese porter from under the ice, taking the toll to 32, including 24 trekkers on the Annapurna circuit and five climbers on a mountain in the area.

Local official Tulsiram Bhandari told AFP that the bodies of the two Slovakian mountaineers and their three Nepalese guides, killed when an avalanche struck the base camp of the 8,167m Mount Dhaulagiri, had now been found.

Thousands of people head to the Annapurna region every October, when weather conditions are usually clear and cool.

The Annapurna Circuit is particularly popular among tourists, and has come to be known as the "apple pie" trek for the food served at the small lodges, known as teahouses, that line the route.

But many appeared to have been unprepared for the conditions on the Thorong La pass, which bore the brunt of Tuesday's unseasonal snowstorm.

Eighteen-year-old trekker Max Weinstein told AFP that hotel staff had told him and a fellow hiker that it was "totally safe" to head up to the pass, which climbs over 5,000m.

Mr Pandey, who is coordinating TAAN's rescue effort, said the disaster underscored the need for a proper weather warning system.

"We have seen far too many avalanches and landslides this year," he told AFP.

"If the government wants to make money from the mountains they need to have better infrastructure in place."

Impoverished Nepal relies heavily on tourism revenues from climbing and trekking.

It has suffered multiple avalanches this year, with 16 guides killed in April in the deadliest accident to hit Mount Everest, forcing an unprecedented shutdown of the world's highest peak.

It was unclear how many people remained stranded in the area on Friday, although the majority are now thought to have been accounted for.

In all, 168 foreign tourists had registered to trek there, but that number does not include their Nepalese guides and porters.

"Our first priority is to reach survivors who need help," said Pandey.

"We are trying to get a clear picture of how many are still missing and unaccounted for," Mr Pandey told AFP, saying that at least two dozen foreigners were known to be safe at a hotel in the area.