THE price of rice leapt more than 16 per cent last month, the biggest rise for several years. But the increasingly wealthy people of Hong Kong are eating less rice now than before, preferring instead the exotic wheat grain pleasures of bread, noodles and hamburger buns. A survey of major supermarkets in Tsuen Wan, Tuen Mun and Yuen Long released yesterday by the Consumer Council found rice prices soared by 16.1 per cent in March. The highest rise was for Thai fragrant rice, the most popular type, making up almost three-quarters of the rice eaten here. A five-kilogram bag of Golden Elephant brand Thai fragrant rice costs around $39.60, up $8 or 25 per cent on February's price. The Consumer Council and rice sellers said the rise was a knock-on effect from steep price increases on world markets last year. Pressure from America had forced Japan and South Korea to open their heavily protected rice markets to international competition, and the Japanese had started buying high quality Thai rice. ''When Japan buys it really does buy,'' said a spokesman for one of Hong Kong's largest rice distributors, Golden Resources Development. ''The Japanese want quality, and they do not mind about the price. They want to buy the best.'' But things could have been much worse for Hong Kong, said Chan Wai-shun, the chairman of the Hong Kong Rice Importers and Exporters Association. ''The Japanese were buying a different type of Thai rice called 100 per cent whole white rice. ''They were not buying fragrant rice. If they had been, the price of fragrant rice would have doubled or tripled.'' Around 72 per cent of Hong Kong's rice comes from Thailand, 15 per cent from Australia, around 13 per cent from China, and a tiny fraction from the United States. But the amount of rice people eat has fallen sharply from 120 kg per person in 1961 to barely 56 kg last year. The Government's principal trade officer John Leung Chi-yan said: ''People are eating bread, hamburgers, noodles and other fast food. ''It is a common trend in other places. People tend to consume less rice as they get richer. For example, people engaged in manual labour usually consume more rice. But now more people in Hong Kong work in the service sector, they work in offices, so they eat less rice. ''A number of rice traders think that the long holidays are also having an effect. At New Year and Easter a significant number of people leave Hong Kong. People are eating abroad instead.'' Hong Kong's rice market is heavily regulated by the Government. Under the regulations in the Reserved Commodities Ordinance dating from the 1950s no one is allowed to sell rice wholesale unless they are registered with the Government. There are 46 companies registered. The Government allots them import quotas every month. In return the companies have to maintain buffer stocks amounting to two months worth of rice consumption. Despite its age, the Government still believes the scheme is worth preserving. ''Even during the June 4 incident or the strikes in the 1960s we still did not have a major rice problem in the territory,'' Mr Leung said.