Sam Lau Kung-shing, chairman of the Tourist Guest Houses Federation of Hong Kong, estimates only 200 to 300 backpackers a month come now, compared with between 400 and 500 in the 1990s.

Their stays are also much shorter. While they once might have stayed one to two weeks, many just stay three to four days as a stopover before moving on to places like the mainland and Vietnam, where traditional life can still be readily found.

The Tourism Board said it had no separate figures for backpackers although its surveys showed overall visitor arrivals had doubled since 1996 to 25 million last year.

These included business visitors and those on guided tours from overseas and the mainland - and more than half were mainland visitors.

'Hong Kong enjoys various advantages as a destination for backpackers, including its safety level, convenience of getting around and ease of communicating,' a spokesman said, adding the board ran museum tours, activity classes and guided walks to 'offer visitors a taste of the distinctive local lifestyle'.

But Mr Lau said these were not what backpackers wanted.

'Backpackers like to see old parts of Hong Kong and its heritage, not going to big restaurants. They like to see ordinary people's lives and wander around seeing things like fishing boats and walled villages.

'But these things have largely disappeared and the urbanisation does not fit their taste,' Mr Lau said. 'They feel that Hong Kong is a big city and no different from where they come from, and they don't like to see just another city.'

But he acknowledged high costs in Hong Kong and competition from other Asian destinations, including Thailand and India, had also had an effect. Another factor was the growing ease of travel to the mainland, which had opened up as a tourist destination in the past decade.

Ten years ago, 90 per cent of his guests at Garden Hostel in Mirador Mansion, Tsim Sha Tsui, were backpackers, now they have dropped to just 70 per cent, Mr Lau said.

He said although backpackers travelled on the cheap, they contributed to the economy by supporting the guest house industry.

Most of the city's 500 guest houses serve backpackers but the 200 establishments in Mirador Mansion and nearby Chungking Mansions, where most of the backpackers stay, were worst affected.

'Many guest house owners are worried. At night, they wait at the bus stops for backpackers,' Mr Lau said.

The growing number of mainland visitors was helping to fill the gap, he said, but he doubted this would be enough to help the hostels survive.

Mong Kok hostel owner Tai Chung-shan said the number of backpackers checking into his 80-room guest house had dropped by nearly half.

Five years ago, between 50 and 60 backpackers from around the world stayed in his Argyle Street hostel each month. The number has dropped to between 30 and 40 a month.

Mr Tai and Mr Lau urged the government to stop demolishing heritage buildings and old street markets to attract low-budget travellers back to the city.