Hong Kong customs officers have arrested an 18-year-old jobless man and seized HK$6.4 million (US$815,000) worth of cocaine in a crackdown on a drug-trafficking syndicate that used an hourly rented industrial unit as its temporary packaging and mailing centre to avoid detection.

They began investigating the syndicate after 3kg of cocaine was found hidden in an Australia-bound air consignment at a logistics centre in Tsuen Wan on July 22.

A follow-up investigation led officers to a Kwun Tong factory building where they lay in wait.

Customs officers have arrested an 18-year-old man and seized 7kg of cocaine.

On Monday afternoon, customs officers intercepted an 18-year-old man at the car park of the building. Another 4kg of suspected cocaine was found in a plastic box he was allegedly carrying.

Senior Inspector Tom Cheung Kwong-tat of customs’ drug investigation bureau on Tuesday said a table lamp was found inside the box.

“We found the box was abnormally heavy after removing the lamp and wrapping material. Further inspection led our officers to the discovery of a secret compartment at the bottom of the box,” he said.

Cheung said the 4kg of suspected cocaine was found in the secret compartment. The man was then arrested on suspicion of trafficking in a dangerous drug – an offence punishable by up to life imprisonment.

He said the 7kg haul of the drug had an estimated street value of HK$6.4 million.

The investigation suggested the air consignment carrying 3kg of cocaine last month was mailed from an hourly rented unit in the same building, according to a law enforcement source.

He said a local drug trafficking syndicate behind the haul used units as its temporary packaging and mailing centres in an effort to evade detection.

Between January and June this year, authorities confiscated 492kg of cocaine, down 62.7 per cent from 1,320kg in the same period of 2021.

Seizures of five major illegal drugs in the city – cocaine, cannabis, crystal meth, heroin and ketamine – more than doubled to 10,627kg in 2021 from 4,678kg the year before. Authorities confiscated 2,895kg of cocaine last year, up 128 per cent from 1,269kg in 2020.