THE Consumer Council yesterday warned the public to exercise caution when confronted by salesmen claiming to be agents of official bodies. The call was made yesterday after numerous complaints about a medical goods firm that claims to have ties with the Hong Kong and Singapore governments. The council was told by the complainants that representatives of the Hong Kong Family Healthcare Centre in Nathan Road had telephoned their offices claiming to be agents of government branches or non-profit making organisations. These included ''a government subvented organisation'', ''appointed agent for the Singapore health authorities'' and ''a government body under the Department of Health''. Complainants claimed they were offered free presentations and trials of equipment which, according to the salesmen, could cure a host of ailments, including diabetes and hypertension. A manager responsible for the products, Chiang Chih-te, said he had no knowledge of his staff claiming to be from any government. He felt it was wrong that the council had publicly named his company. The council had received 10 complaints against the firm since December. The products in question varied in price from about $200 to $1,300. Customers called the council when they became suspicious about the products and the company's authenticity. A spokesman for the Singapore High Commission in Hong Kong said they had received numerous inquiries about companies in Hong Kong with possible bogus ties with them. A spokesman for the Department of Health confirmed that similar inquiries and complaints had been received.