THE BBC World Service Dateline East Asia was re-launched on Monday on RTHK Radio 3, with a new double-length format of 30 minutes each weekday. ''The expansion is a reflection of East Asia's growing economic and political significance in world affairs,'' said Mr Richard Oppenheimer, deputy head of the BBC Southeast Asian Service. Greater depth of analysis and an increased variety of subject matter is promised, together with a world news summary and an East Asian business round-up. Acting Dateline editor, Mr Tim Luard, who reported from Tiananmen Square on the 1989 student protests, noted the programme's catchment area stretched from Burma to the Pacific and from the Russian northeast to Papua New Guinea, and included most of the world's remaining communist regimes as well as Japan and the fast-growing countries of Southeast Asia. Hongkong's pivotal position would be fully reflected in their coverage, Mr Luard said. ''We recently interviewed the Governor, Mr Chris Patten, as part of a special report on the territory and, in future, we will have greater flexibility to explore such issues,'' he said. ''Our new Business Developments slot, which will carry the major financial stories of the day as well as the latest stock market trends, should be of particular interest to Hongkong.'' Cambodia seems likely to feature strongly, thanks to the imminence of UNCTAD-supervised elections due in May. Dateline 's Mr Iain Simpson is based in Phnom Penh and the programme's editor, Mr Michael Williams, is on secondment there as the United Nation's Deputy Director for Human Rights. Coverage of the PRC should also be well-informed, because three of the six-strong team of reporters, Mr Tim Luard, Mr Simon Long and Mr Francis Markus, speak Mandarin. Ms Catherine Napier, a Cambodian specialist, Mr Jonathan Miller, and Mr Stuart Bruseth complete the mobile staff. Dateline 's co-presenters will be Ms Kathryn Davies, who has worked extensively throughout the region, and award-winning journalist Mr Mike Bullen who has been at the helm for the past two years.