WHEN Graeme McDougall's Queensland company began exporting its vegetarian products, if you had asked him whether Hong Kong offered a market he would have laughed. Four years on, the Hong Kong vegetarian market is worth an estimated US$500 million, Mr McDougall's products are in 500 stores in the territory including Wellcome and Park 'N Shop and the company is contemplating a joint venture in China. ''If you had asked me about Hong Kong, I would have thought there was not much of a vegetarian market there,'' said Mr McDougall, managing director of Longa Life Vegetarian Products. ''To our surprise, we have shown there is a huge market. The younger generation is becoming health conscious, especially women, who are conscious of their complexion and body weight and vegetarianism wins on both those scores.'' Longa Life sent its first shipment to Hong Kong in January, drawing on the experience of its food technologist, John Menzics, a vegetarian, as is Mr McDougall, who worked in the territory for two years and convinced Mr McDougall of its huge potential. Now its wheat gluten-based spicy sausage, vegetarian hotdog and Lubular, luncheon meat-style vegetarian chicken and vegetarian ham can be found in the freezer compartment of most major stores. As well as Hong Kong, Longa Life is selling in Singapore, Malaysia, Kuwait, New Zealand and Taiwan - its Hong Kong agent is the Taiwanese company Dragon Race Enterprises, with whom it is considering a Chinese joint venture. Early next year, a new product will be joining the current Longa Life range in Hong Kong, a vegetarian prawn, a seafood taste created from starches, gums, vegetable oil and dairy proteins, but with no artificial colourings or seafood pastes.