A Mainland resident and two Taiwanese people have been arrested in an alleged passport fraud, the Immigration Department says.

Immigration investigators monitored a 28-year-old Taiwanese woman at the airport on August 28, before she left for Shenzhen. She is believed to be active in illegal immigration activities.

She returned to Hong Kong from the Mainland yesterday and proceeded to check in for flights to both Chicago and Taipei. After departure clearance, she handed a small package to a 42-year-old Taiwanese man near the boarding gate for the flight to Taipei.

The man met a 29-year-old Mainland woman, handed her something, and went into a restroom. Both of them then went to the boarding gate for the Chicago flight. A Mainland passport and a boarding pass for a Guangzhou-bound flight in the name of the Mainland woman were found in the restroom.

At the boarding gate, the Mainland woman presented a boarding pass and a suspected forged Taiwanese passport with a counterfeit bio-data page and US visa. All documents were in the Taiwanese woman's name. All three people were arrested.