A boy who kicked a police officer in the face will spend more time in youth detention for kicking another man in the head as he lay on the ground.

The 17-year-old boy, who cannot be named for legal reasons, was sentenced in the children's court on Thursday to eight months in detention on charges of affray and intentionally causing injury.

However, the boy will be freed much sooner than that as the magistrate ordered the sentence be served concurrently with another term the teenager was given for kicking a police officer at Highpoint Shopping Centre in December last year.

The policeman was left battered after being kicked in the face by the defendant.

The teen was controversially granted bail after assaulting the police officer and initially avoided a conviction but was later given four months detention on appeal.