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.