POLICE believe recent flooding in Guangxi and Guangdong provinces might have held up drugs from the Golden Triangle. Detective Chief Inspector Tony Singleton of the Narcotics Bureau said there had been a big pile-up of drugs in China because of the rain. ''It's because roads there are not so good, making shipment difficult in rainy weather. Now that the weather has cleared up we are concerned the syndicates have started to get the drugs through again,'' he said. Mr Singleton said Chinese police have been notified. Commissioner of Police, Eddie Hui Ki-on, and his senior aides are to visit Beijing next Monday, and one of the issues to be discussed is cross-border drug trafficking. Both Hong Kong and Chinese security authorities are concerned drug traffickers are using land routes to smuggle drugs into Hong Kong from the Golden Triangle via Yunnan, Guangxi and Guangdong provinces. Mr Singleton said the shortage of drugs over the past month because of the floods had pushed up local wholesale prices by 10 to 20 per cent. Narcotics Bureau officers raided an alleged heroin storage area in Cheung Wah Street, Shamshuipo, and seized 10.6 kilograms of No 4 heroin worth $10 million on Tuesday night. They arrested three men aged between 30 and 34 who are believed to be core members of a drug syndicate responsible for supplying heroin in Kowloon. ''We believe the high-grade heroin had just arrived from the Golden Triangle via China on Tuesday morning,'' Mr Singleton said.