Thirty-three people, aged between 15 and 65, have been rounded up in a crackdown on a Tuen Mun faction of the Sun Yee On triad, according to police.
The eight-day operation, codenamed Lightsmoke, targeted the faction headed by one of the triad's "red-pole fighters" known as Cripple Wing.
Acting Chief Inspector Man Yu-ching of the New Territories North regional anti-triad squad said about 50 officers had been deployed each night for the raids, which ended on Sunday.
"The focus of this operation was to suppress the income sources of the triads," she said.
"We believe the sweep has dealt a blow to the triads and resulted in active triad members keeping a low profile."
Pubs, pool halls, gambling dens and residential flats in the district were targeted.
Twenty men and 13 women were picked up during the raids. Police said some were suspected members of the Sun Yee On triad, but no high-level triads were caught.
They were arrested for various offences, including drug trafficking, wounding, criminal intimidation, claiming to be triad members, possession of offensive weapons and illegal gambling.
All have been released on bail pending further investigation.
Officers also seized illegal drugs with an estimated street value of HK$72,000 and confiscated an extendable baton.
Man said the triads were involved in trafficking illegal drugs, running gambling dens and controlling entertainment venues.
Police figures show there were 2,340 reports of triad-related crimes last year, a 6 per cent rise from 2,207 in 2011.