Hong Kong police have arrested two local men after discovering HK$77 million (US$9.9 million) worth of heroin in a crackdown on a triad-controlled drug trafficking syndicate.

After receiving a tip-off, police began investigating the syndicate, which used an upscale flat for storing narcotics, according to the force on Thursday.

On Wednesday morning, officers from the narcotics bureau lay in wait at Mei Foo Sun Chuen, a private housing estate in Lai Chi Kok.

Shortly before 10am, a car carrying two men drove in and pulled over on Broadway and one of them left the vehicle and entered a nearby building.

Police seized 265 slabs of suspected heroin in total.

As the man left the building, officers moved in and intercepted him. Police seized 19 slabs of suspected heroin – weighing 6kg in total – in a bag he was carrying.

Police arrested him and the other man on suspicion of trafficking in a dangerous drug.

On the same day, the two suspects, aged 40 and 41, were escorted to a high-end flat on Sham Mong Road in Cheung Sha Wan, where officers discovered another 246 slabs of suspected heroin with a total weight of 77.5kg, according to Senior Inspector Law Kai-yin.

He said the illegal narcotics seized in the operation had an estimated street value of HK$77 million.

“Police have successfully prevented this large quantity of illegal drugs from circulating in the underground market,” Law said.

He said the investigation indicated the haul involved a triad-controlled drug trafficking syndicate and the operation had struck a major blow to its income source.

As of Thursday afternoon, the two suspects were still being held for questioning.

In Hong Kong, drug trafficking is punishable by up to life in prison and a HK$5 million fine.

Provisional figures show seizures of five major illegal drugs in the city – cocaine, cannabis, methamphetamine, heroin and ketamine – rocketed by 55 per cent to 7,905kg last year from 5,075kg in 2021.

But the amount of heroin seized dropped 20 per cent to 327kg in 2022 from 410kg the year before.