The head of Guangdong's anti-drugs commission says mainland authorities may impose tougher punishments, including a year in a labour camp, on Hongkongers arrested for using drugs. Chen Shaobo, chief executive officer of the Guangdong Narcotics Control Commission, said yesterday that drug abusers faced up to 15 days in custody after being arrested across the border, but that those arrested more than once could face a year in a labour camp and compulsory drug-rehabilitation treatment. Mr Chen was speaking at a seminar attended by dozens of anti-drugs officers from Hong Kong, Macau and Guangdong. They had gathered to share their experiences in fighting drug abuse and smuggling. Meanwhile, officials said the first drug arrest had been made at the new Western Corridor checkpoint less than two weeks after its official opening by President Hu Jintao on July 1. A 43-year-old Hong Kong man was arrested after officers found half a tablet of suspected Ecstasy. He was released on bail. Extra customs officers have been sent to border checkpoints to prevent drug dealers taking advantage of heavy summer traffic to smuggle drugs into Hong Kong. In a parallel move, mainland officers have enhanced inspections of cross-border travellers, according to Ben Leung Lun-cheung, head of the customs department's drugs investigation bureau. Mr Leung said officers were on the alert for a possible influx of cheap cocaine from South America after the price of the drug on Hong Kong's streets plunged by almost half. 'We have also enhanced the exchange of intelligence with mainland authorities to crack down on drug-related smuggling activities during the summer holidays,' he said. He said drug traffickers usually explored ways to smuggle drugs into Hong Kong after the opening of a new border checkpoint. 'It's a challenge to us, but we spare no efforts to deal with this,' he said. Intelligence showed that drug couriers were smuggling drugs into the city in luggage, food or hollowed-out books. Mr Leung said enhancing inspections at border checkpoints could also have a deterrent effect as more young people travel to cities in Guangdong to take drugs during the summer holidays. Mr Leung said more sniffer dogs were being used at border checkpoints, along with hi-tech equipment such as X-ray machines and ion scanners. Figures from the Central Registry of Drug Abuse showed the number of new ketamine abusers under 21 years of age had increased to 401 in the first quarter of the year, from 252 during the same period last year. In the first five months of the year, customs officers investigated 272 drug cases and arrested 259 people. During the same period last year, 242 cases were investigated and 233 people were arrested. Sally Wong Pik-yee, commissioner for narcotics with the Security Bureau, admitted that the real number of drug abusers, especially young ones, was much higher than the official estimate. 'In recent years, the overall number of drug abusers in Hong Kong has been dropping, but the trend for youngsters under 21 to take drugs has been rising significantly,' she said. Mr Leung said officials feared that the drop in the price of cocaine heralded an effort by South American dealers to tap a new market. He said the average retail price of cocaine had dropped to as low as HK$587 a gram, from more than HK$1,000 two years ago. 'We don't rule out the possibility that they are trying to explore a new market by lowering the street price of the drug,' he said. Figures from the Central Registry of Drug Abuse showed that the number of new cocaine abusers under 21 had doubled to 110 last year from 42 in 2005. Twenty-nine new cocaine abusers were registered in the first quarter of the year. Officers said cocaine abuse in Hong Kong was previously limited to the wealthy, but more young people were now taking the drug.