LEGISLATORS have been refused a detailed account of the Government's telephone bugging activities, despite a promise of one. A letter from the Security Branch to the Legislative Council's Information Policy Panel chairman, Emily Lau Wai-hing, said officials could not be sent to attend tomorrow's meeting, which had on the agenda ''telephone interception''. The branch agreed last month to send officials. Legislators intended to ask the Government under what circumstances it would conduct telephone interception and about its checks-and-balances mechanisms. The topic was added to the agenda after former Independent Commission Against Corruption (ICAC) director of operations Alex Tsui Ka-kit alleged the Government had bugged the telephones of former secretary for transport Yeung Kai-yin and former executive councillor Rita Fan Hsu Lai-tai. Principal Assistant Secretary John Shannon said in the letter that it would be inappropriate to discuss telephone interception with legislators because the topic was under review by the ICAC review committee and also the Law Reform Commission. The Government has asked the Law Reform Commission to examine the Telecommunication Ordinance as part of its examination of privacy legislation. Miss Lau said: ''I could not understand why the Government could not discuss it with us when the topic was under review. That's unreasonable.'' She said the Government had said ''several times'' in the past few weeks that it would send officials. However, Mr Shannon supplied legislators with a two-page paper on telephone interception. The paper said telephone interception had been found by governments throughout the world to be ''an important means in the prevention or detection of serious crime and in maintaining the integrity of their territories' security''. ''The Hong Kong Government is no exception,'' the paper said. It said telephone interception in Hong Kong was used only in the prevention or detection of serious crime, and in monitoring threats to security. The paper also revealed that only the police and the ICAC would carry out interception. Stringent safeguards had been in place to ensure that there was no abuse, it said. Telephone intercepts had to be authorised by the Governor, who required detailed justifications to satisfy him that they were necessary and that information could not be obtained any other way.