Customs officers at the airport have seized around 13 kilogrammes of heroin hidden inside nylon mats brought into the city from Thailand.

The haul, estimated to be worth around HK$10 million, was discovered in a passenger's suitcase on Saturday, officials said.

A 36-year-old man who flew in from Bangkok was arrested.

"Following the resumption of normal travel and exchanges with the mainland and other parts of the world, the number of visitors to Hong Kong has also been increasing steadily. Customs will continue to apply a risk assessment approach and focus on selecting passengers from high-risk regions for clearance to combat transnational drug trafficking activities," a statement from the department said.