GARMENT retailer Theme International Holdings is arranging a listing on the Hong Kong stock exchange to raise funds for the expansion of its retailing operations. The company holds all the retail and related operations of Mercuries-Jeantex Holdings, which includes the brand names Theme, Theme Plus and Body Glove. Proceeds from the listing will be used to set up 12 shops in Hong Kong, four in Japan and one in Shenzhen during the financial year to March 31, 1995. ''Our main focus will be Hong Kong; Asia will be second,'' said chairman and chief executive officer Kenneth Lai Ngan-long. He said the 12 shops to be set up in the territory would include a few franchise shops, and that Theme International would not be responsible for their operating costs. Theme will also open a 2,000-square-foot shop in Kowloon next month, with an investment of more than $1 million. Mr Lai said rents - averaging $100 to $150 per sq ft - accounted for 30 per cent of total operating costs of a shop. Theme currently has 49 shops in Hong Kong and four in Macau, of which 18 are franchise shops. Their sizes range from 600 to more than 4,000 sq ft. Mr Lai said that although all the shops were rented, they would not be subject to much pressure in the rising rent market. ''Our landlords are reasonable and impose reasonable rises. We also maximise our sales areas and minimise storage areas by replenishing the stock of each shop every day,'' he said, adding that the rent-to-turnover ratio had been falling in recent years. Some of the shops have consignment counters for other suppliers of related products, such as shoes. ''We want to serve as one-stop shops,'' Mr Lai said. Net proceeds from the flotation will also be used to fund Theme's Japanese project, whereby it will run a joint venture with a Japanese designer and retail the clothes he designs. Mr Lai expects to set up four such retail shops in the next financial year to spearhead the establishment of a retail chain in Japan. The company is also planning to set up a shop in Shenzhen in co-operation with Guangdong Enterprises, to add to its five existing mainland outlets in Guangdong province, Beijing and Shenyang. Mr Lai said he hoped to launch distribution franchises for Body Glove in the region in the next financial year. In the year to March 31 the group posted an after-tax profit of $28 million - of which Hong Kong accounted for 90 per cent - a considerable improvement on its $5 million gain in 1992, and its $2 million loss in 1991. Turnover stood at $300 million for the year to March 31, compared with $200 million in 1992, and $150 million in 1991.