Police confiscated cannabis plants with a street value of HK$30 million in raids on three remote village houses in the New Territories.
A police source said it was the biggest such seizure in a single operation since 2007.
Four people – three Hong Kong men and an Indonesian woman aged 22 to 51 – were arrested when officers from the narcotics bureau raided the cannabis farms in Sheung Shui on Thursday afternoon after a two-month investigation.
About 1,300 cannabis plants and more than 200 grammes of cannabis leaves and equipment were seized. Police believed the drugs were for local consumption.
More than HK$5 million including money in 11 bank accounts and two cars were also seized as crime proceeds.
The houses were sealed off on Friday as the investigation continued and the four suspects were being questioned. Police were still investigating how long the gang had been operating.
It was the second raid on cannabis growers in two months. In February, police seized more than 500 cannabis plants and 1.1kg of cannabis buds in a Yuen Long house. A man and a woman were arrested. Police valued the haul at HK$11 million.
“Cannabis leaves have an estimated street value of HK$270 per gram, while cannabis buds are worth about HK$190 a gram,” another police source said.
Police figures show cannabis seizures in the city surged by 96.2 per cent to 255kg last year from 130kg in 2015. Law enforcers seized 99kg of cannabis in 2014 and 85kg in 2013.
Fighting illegal drugs was one of the police commissioner’s priorities this year, according to the force website.