Although the number of complaints are relatively small - just 10 cases in 2003 compared with 49 last year and five so far this year - the council fears that many more cases go unreported because the amounts taken are small and people who are deceived feel embarrassed to come forward.

Instead of running health-care services, the companies involved in most of the consumer disputes usually claim to have a link with a group of private clinics or laboratories to provide services to their members at a discount rate, usually 10 or 20 per cent and perhaps even as low as half price.

'But when the members visit the doctors, they find they are charged at the normal rate,' said Connie Lau Yin-hing, deputy chief executive of the Consumer Council. 'In some cases, the doctors even confirm to patients that they do not have any link with these organisations.'

However, the companies' contracts for their members were often so vaguely termed that they did not provide enough proof of fraud to bring a prosecution, Ms Lau said.

The complaints so far received by the Consumer Council involve about 10 companies, with one or two having closed down. She said this made investigation more difficult.

Membership for the schemes in question usually costs a few hundred dollars for one person for one year, and about $1,000 for a family of three or four.

'I guess the complaint figures show only the tip of the iceberg, as some consumers choose not to come forward to disclose their situation in view of the relatively small amount of their financial losses - usually a few hundred dollars,' Ms Lau said. 'However, these companies may be making a fortune if a large number of people have fallen into the consumer pitfall.'

Mrs Lee said she had made a report to police but was told that prosecution was difficult. She was advised by police to lodge her complaint with the Consumer Council. 'Police say the company is very smart in making use of the legal loopholes, because it had actually sent a membership card to my home, together with a receipt and some documents to confirm my membership,' Mrs Lee said.

'Police say it is difficult to bring charges on this kind of 'misrepresentation' by the sales representatives, because they provided information to their clients over the phone instead of having anything in black and white.'

Mrs Lee said she was approached by the company through her mobile phone and was duped into disclosing her credit card number to the salesperson. 'I don't know where they got my number from, and they called my mobile phone a few times,' she said, adding that the salesperson on the phone was patient and explained to her the importance of health protection.

'She asked for my address to send me information about the scheme and for my credit card number, saying that would only be used as a reference. I thought it would be safe as long as I had not signed any document or credit card slip,' she said.

'But a few days later, I received a receipt and a pile of documents from the company to confirm my membership. I was shocked to find out that they had already charged my credit card account for payment.'

When the South China Morning Post called the company for information about its scheme, a manager who identified herself as Ms Law refused to specify the privileges under the company's membership.

'There are usually discounts and sometimes free medical examinations,' Ms Law said. 'But the privileges vary from scheme to scheme and are different from doctor to doctor ... You may want to check it out on your own from our website.'

The website for the most part spelled out the minimum medical charges and did not give details about the business relationship between the company and its affiliated clinics and laboratories.

Ms Lau admitted that there were technical difficulties in taking legal action against such companies because they did not come under the supervision of the Department of Health, which licenses private hospitals, or the Hong Kong Medical Council, which registers doctors. 'There are grey areas for those companies. The business relationship between those companies and the clinics or laboratories is unclear,' she said.

Legislator Kwok Ka-ki said he had brought the issue to the attention of the Health, Welfare and Food Bureau to prevent more patients from falling into the insurance trap.

'But the health officials admit that those companies are not under any legislative control and there really is nothing they can do about those commercial activities,' said Dr Kwok, deputy chairman of Legco's health services panel.

Ms Lau said it was unclear how many health-care management companies were operating in Hong Kong as they did not need special registration.

'Of course there are health-care companies in the market that operate with honesty, but our role is to target the black sheep,' she said.

Ms Lau said health-related businesses had boomed in the two years since the Sars outbreak. She expected that plans by the Hospital Authority to drastically increase medical charges would likely boost the health-care management market further.

The cash-strapped authority has recently announced that 69 expensive drug items, including 26 cancer drugs, will be fully paid by patients in public hospitals.

'With more new health-care services emerging in the market, we expect to receive more complaints,' Ms Lau said.

For the category of conventional health and life insurance, the number of complaints lodged with the council has fallen from 78 in 2003 to 53 last year. There are six so far this year.

The complaints are mostly to do with misrepresentation by insurance agents, such as their failure to thoroughly explain to clients the items of exclusion on a policy, or the waiting period before compensation will be given, a common dispute for which consumers try to seek compensation.

The Hong Kong Federation of Insurers represents 134 insurance companies that take up 90 per cent of the market share. According to the federation, the Insurance Agents Registration Board is responsible for handling complaints against insurance agents. Over the past two years the board has received no complaints about misrepresentation by its members on the issue of excluding policy details, or about waiting periods for health care and life insurance compensation claims.

The Consumer Council's Ms Lau said: 'Since the council has no legal power at all, what we can do is to announce the companies which have been found to breach their business ethics. We would rely on consumers themselves to stay cautious and seek more information when they plan to join any schemes, especially services or products which are completely new in the market.'