Customs officers have seized their biggest ever haul of ketamine, a 412kg stash with a street value of HK$47 million.
It is more than triple the amount of ketamine seized by customs in the whole of the past two years.
The 23 bags of drugs were found in a container that arrived at the Kwai Chung container terminal from Hangpu port in Guangzhou on Wednesday en route to Malaysia.
The ketamine was disguised as a resin used in the manufacture of plastic products and was hidden behind 493 bags of genuine resin.
Officers became suspicious about the container, one of 1,200 on board the mainland vessel, and a sniffer dog managed to root out the drugs.
'It is common resin imported into the mainland from overseas via Hong Kong for the manufacture of plastic products,' Lam Tak-fai, of ports and maritime command, said.
'But it is very rare that raw material is exported from the mainland to other countries. Officers were suspicious and selected it for a check.'
After an X-ray found nothing suspicious, seven-year-old sniffer dog Wagar was put to work and found the drug. No arrests have been made.
Senior Superintendent John Lee Cheung-wing, head of the customs drug investigation bureau, said the force was working with authorities on the mainland and in Malaysia.
It was the second large drug-related haul reported by customs in as many days, but officers insisted again that the city was not being used as a drug transit hub.
'Our crackdown demonstrates we are determined to fight drug trafficking and shows zero tolerance towards such activities,' Lee said.
The haul was discovered during a three-day operation in which officers stepped up the inspection of containers from ports on the Pearl River Delta. During the operation, which ended on Wednesday, more than 1,200 cargo containers were checked.
On Thursday, customs revealed they had seized 700kg of flu tablets in six consignments at the airport's cargo terminal this year. The tablets were bound for underground factories on the mainland, where they would have been converted into the drug Ice.
Customs seized 75kg of ketamine last year, 47kg in 2010 and about 380kg in 2009. Their previous biggest seizure of 398kg of ketamine was in 2008. Lee said ketamine was sold for HK$116 per gram on the streets, where its purity varied from five to 95 per cent.
'Drug dealers mix chemical additives such as caffeine, sulphenamide and sugar to increase the volume and make more money,' he said. Ground glass had also been found in drugs seized on the streets.
Ketamine, originally used as a horse tranquiliser, was designated as a dangerous drug in 2002.
It was the most abused psychotropic substance among reported drug abusers last year, according to the Central Registry of Drug Abuse, held by the Security Bureau's narcotics division.
The registry figures showed that the number of new drug abusers under 21 reported last year was 1,229, down 32 per cent from 2010.
Paul Lo Po-sing, a social worker who leads a youth outreach team for the Evangelical Lutheran Church of North District, said the figures were the tip of the iceberg and failed to reflect the seriousness of the local drug situation.
He said that while young addicts used to take drugs on the streets or in parks, many now 'go to their own or friends' homes or upstairs pubs to take drugs'.
Lo said peer influence and the availability of illegal substances were the main reasons why young people abused drugs.
He urged the government to allocate more resources to tackling the problem.
Police found this much ketamine in the city's biggest haul of the drug. It was found at an industrial unit in Tsuen Wan in 2006