CCTV footage of a Boxing Day assault of a police officer shows a teenager rushing through the crowds at Maribyrnong's Highpoint Shopping Centre to kick the officer in the face.

In the footage, the officer is kneeling on the ground attempting to detain a 16-year-old boy who was resisting arrest for shoplifting when the other teenager enters the scene.

The attacking teen is seen swinging his leg towards the police officer before he is briefly held back by another man in the crowd, and then he runs away.

Police have released the footage in the hopes that witnesses can help them track down the assailant.