The two-day operation saw the closing down of two illegal venues in Tai Po and Sheung Shui, two areas in the New Territories, Hong Kong.
Police arrested 34 men and 14 women aged between 17 and 65, seizing mahjong tables, arcade machines, cash, gambling chips and illegal drugs.
Over half of the suspects meanwhile received fines for violating rules that banned gatherings of more than two people amid the coronavirus pandemic.
“The venues posed a risk of transmitting the coronavirus because of poor ventilation and hygiene. It is irresponsible for them to set up such illegal gambling dens or drug dens,” said Tai Po assistant district commander Johnson Chong Shing-yat.
The arrests come just a day after Hong Kong police shut down an illegal casino for wealthy gamblers in the Tsim Sha Tsui shopping district.
A total of 16 people were arrested, including a barrister and four company directors. Police also seized HK$24m (US$3m) in gambling chips, and HK$215,000 in cash.
A police source said: “A single bet involving more than HK$100,000 was placed on a baccarat game. We believe its daily turnover reached up to HK$10 million, and the gang could pocket HK$1 million per night.”
The gambling racket reportedly spent over HK$130,000 a month to rent the penthouse in The Masterpiece, a high-end residential block comprising of 345 luxury flats, a shopping centre and a hotel, in a bid to avoid attracting police attention.