The journalist had been helping to provide video coverage of the protest, and had been demanding police explain why they were trying to snatch mobile phones away from two young women who were being questioned.
Police rushed forward, and the journalist was pushed, and hit on the hand by a baton. One officer shouted twice “are you trying to pervert the course of justice?”
His finger was left swollen, and he was unable to extend it fully for a time.
An RTHK spokesman said the broadcaster severely condemns acts of violence against journalists and reserves the right to take further action.