Hong Kong may be increasingly exposed to the mainland's Aids epidemic because of increased cross-border travel and some local people's high-risk behaviour in China, an Aids expert warned yesterday. Dr Homer Tso Wei-kwok, chairman of Hong Kong's Advisory Council on Aids, said he wanted answers from the SAR Government as to how Hong Kong was going to avert a crisis. 'We are a little bit ahead of [the mainland] in prevention but it does not mean we will be spared,' said Dr Tso. He was speaking to the South China Morning Post after attending the opening of the Community Forum on Aids at the Convention and Exhibition Centre. The mainland's Health Ministry last week acknowledged the country was facing an HIV/Aids epidemic. It said there could have been more than 600,000 HIV-carriers on the mainland up to the end of last year, rather than the official number of 26,058 cases. Dr Tso said he hoped there would be a change in how the SAR Government viewed Aids as a result of what was happening on the mainland, rather than treating it as an 'invisible problem'. He said the administration should consider the possible impact of its $18 billion drive to promote mainland tourism - announced last Friday - on HIV and sexually transmitted diseases in the SAR. Dr Tso also said there was evidence there could be an 'impending explosion' of HIV in some sections of the local population, such as intravenous drug users and sex workers. A series of surveys of high-risk groups by the Community Planning Committee, an Aids advocacy group, found that the most popular places to meet gay sex partners were bars (46 per cent) followed by gay groups (45 per cent), saunas (40 per cent) and the Internet (39 per cent). The average age of survey respondents was 30 and the average length of time they had been having sex 7.5 years. Last week, the South China Morning Post reported that more than one in two cross-border truck drivers had had sex with mainland prostitutes in the past six months. The Community Planning Committee, which organised yesterday's Aids forum, said its work with high-risk groups was being interrupted because of a funding rejection by the Aids Trust Fund, part of the Health and Welfare Bureau. The committee works with sex workers, gay men, cross-border travellers, youths, drug users and HIV patients.