Hong Kong has seen a further slight decline in drug abuse, but it is still too early to be optimistic, narcotics experts have warned. They say the different pattern of drug abuse might affect the figures and tackling the problem became more complicated as more drug users were crossing the border for cheaper drugs. Winnie Tsui Siu-lo, acting commissioner for narcotics, attributed the year-on-year 5.1 per cent fall of drug abusers to accelerated crackdowns on drug abuse on the mainland. She also said the changed pattern of drug abuse might play a role. 'We have cracked down on some really big rave parties and seen a significant drop in ketamine users, but we need to keep alert on whether people use drugs at home parties or private venues. We also notice a lot of people are going to the mainland for cheaper drugs,' Ms Tsui said. James Chien Ming-nin, foundation president of Pui Hong Self-help Association, said the agency, which works with drug abusers, had noticed an increasing number of drug addicts were crossing the border where drugs are cheaper and easier to find. 'Some said they went to a 'heroin restaurant' together. They paid at one window and moved to the next window where they received a heroin injection. At the third window somebody cleaned the needle hole. Everything was systematic,' Dr Chien said. Philemon Choi Yuen-wan, chairman of Action Committee Against Narcotics, said the biggest difficulty in tackling drug abuse was finding the abusers 'They are hiding away and they won't come to us or agencies for help. How can we formulate any strategies when we don't know the exact number of people using drugs?' he asked. Dr Choi suggested curbing drug abuse could be much easier with a judicial change, such as introducing compulsory drug rehabilitation and a drug court. The three were speaking yesterday at the first day of the Fourth Tripartite Symposium on Drug Abuse, where experts from Hong Kong, Macau and the mainland are exchanging ideas on measures to stop drug abuse and cure addiction.