ONLY a fraction of lawyers in Hong Kong could conduct a complicated case in Chinese after 1997, the chairman of the Bar Association, Jacqueline Leong, said yesterday in a strong drive against any change in language. Miss Leong was unwilling to say exactly how many were up to the task, but she said: ''It is widely acknowledged that the entire legal profession would have to be re-educated to a considerable degree if Chinese were to be used in cases in the higher courts.'' Senior legal sources said it was believed only about two per cent of lawyers would be able to cope with such a move. A working group under Mr Justice Litton is considering if it is possible to increase the use of Cantonese in the Supreme Court, while another group under Mr Justice Chan is looking at the District Courts. But Miss Leong warned that any move to replace English with Chinese as the language of the law could put Hong Kong's international standing in jeopardy. She said it was virtually impossible to translate into Chinese the many thousands of previous cases on which the Common Law was based. ''There is no doubt English is the language of the Common Law,'' she told City Polytechnic law students at a Law Week discussion. ''You know how difficult it is to describe in English the technical terms, the expressions, the meanings in the legal system.'' In Chinese it was even harder, she said. Similar difficulties would be faced in translating important cases that would arise in the other Common Law systems in the United Kingdom, Canada, Australia and New Zealand. ''As a matter of mechanics, because of the difficulties involved, it might very well result in a simple alternative being put forward.'' This would probably mean a codified, written law for Hong Kong designed by a future government. This could frighten off foreign investors. ''The legal system is the lynchpin of every successful society,'' she said. ''The Common Law system has been tried and tested over many hundreds of years. ''It has evolved successfully in changing times, changing attitudes and changing values. ''It would be unfortunate for Hong Kong if it became unplugged from the international Common Law system. ''When an international business looks for a place to base its regional operations one of the primary things it looks to is the legal system there. ''Many international businesses have chosen to locate in Hong Kong for this reason. Any change might well have an unsettling effect.'' Cantonese was used in Magistrates Courts, but even there lawyers still argued points of law in English, she said. In complicated cases at higher courts which hinged on points of law, it would be even more difficult to do away with English, she said. ''The Malaysian Government for political reasons imposed Malay as the only language of the courts. ''The lawyers having grown up in a country using English as the language of the law found it very difficult to argue their cases, and the Government was forced to backtrack and give people the option of using English,'' she said. The president of the Law Society, Roderick Woo Bun, said far more needed to be done to make Hong Kong's laws accessible to the man in the street. ''Things like the lease of a house are produced entirely in English, when more than 90 per cent of the population speak Chinese. ''These everyday documents should be couched in both languages.'' The same applied to lists of charges in a criminal case, he said.