A 15-year-old girl was found carrying drugs at Lo Wu on Sunday night, police said. She is the second teenager caught allegedly handling drugs in five days.
The girl, surnamed Chan, passed through the border, which was busy with people coming back to Hong Kong, at 11pm - an hour before the gates closed.
Police had received tip-offs that drug traffickers were using young people to transport drugs from the mainland to Hong Kong. They said they had followed Chan to the Lo Wu station on the MTR East Rail line, where they caught her with 2kg of Ice. The drugs, estimated to be worth HK$1 million, were hidden in a box of pineapple cakes.
Chan, a new immigrant who came to Hong Kong last year to reunite with her family, is a Form One student, police say.
On Thursday, customs officers caught a 14-year-old boy at the Kwun Tong MTR station who they say had 3kg of ketamine hidden in a fast-food takeaway bag. Two other youngsters were caught last month with drugs in their possession.
Andrew Siu Man-hong, an assistant professor at Polytechnic University, says drug traffickers use teenagers because they can recruit them easily.
"Some youths think they won't be punished severely because they are under 16 years old, and are just handling small amounts of drugs," he says. But once they start trafficking, it will be hard for them to stop because it is a fast and easy way to earn money, Siu added.