In operations conducted since early November, officers found 52,000 ecstasy pills in parcels intercepted at air cargo terminals and in town.
The pills were sent from Europe in parcels that were declared to be containing items such as sweets, coffee and bed sheets.
A 49-year-old man was arrested in Mong Kok on Thursday for allegedly receiving one of the parcels.
In another operation this week, officers seized 153 kilogrammes of cannabis buds, most of which were hidden in boxes of cereal shipped in from Canada.
The rest of the drugs were found in a warehouse in Tuen Mun.
Two men aged 25 and 43 were arrested in connection with this find.
At a press conference, divisional commander Alan Lau said Customs will step up inspections and enforcement ahead of the holidays.
“We believe there is an increasing trend due to the approaching Christmas and New Year holidays. We believe the drug traffickers are making use of this opportunity where parties and nightclubs would enable people to gather. These traffickers would take this opportunity to sell party drugs… in these venues,” Lau said.
Officers also said they have seized 690 kilogrammes of cannabis this year, almost double the amount seized in 2020.