The specially-designed sticker with a hidden code can only be revealed with the use of a special optical device, Yilan police said, adding that the stickers would not mar the appearance of stylish bicycles.

The hidden code would interface with the police's data bank where the personal information of bike owners would be stored, the police explained. If a bike carrying the invisible sticker is stolen and the police find it, they could easily identify the owner, based on the hidden code, they said.

With effect from Tuesday, cyclists with ID cards can ask for the free stickers at any police station around the county, and at the same time have their bikes registered as a precaution against theft, the Yilan police said.