Customs officers on Sunday said they charged two men suspected of trafficking and possessing dangerous drugs worth more than HK$2 million.

The two were arrested on Saturday at the Hong Kong-Zhuhai-Macau Bridge border checkpoint. Officers said they were suspected of carrying about 850 grams of etomidate powder as they entered Hong Kong in a seven-seater.

"Although initial X-ray images showed nothing suspicious [with the powder], officers noticed that the sealing strips on two cans of adult formula milk powder had been opened, which was clearly different from the sealed strips on new packaging," said inspector Ho Pui-yee of the Cross-boundary Bridge Command.

"Officers immediately decided to conduct a more thorough inspection of these two cans. After opening the packaging, officers found two bags of white powder. They then conducted a rapid drug test on the powder, which came back positive for etomidate," she added.

Officers then arrested both the driver, 41, and the passenger, 49, on the spot.

Later on, a suspected etomidate capsule was found in the personal belongings of the arrested male passenger, customs said.

The driver was charged with one count of trafficking in a dangerous drug, while the passenger has been charged with one count of trafficking in a dangerous drug and one count of possession of a dangerous drug.

The two suspects will appear at West Kowloon Magistrates' Courts on Monday.