This is the moment a Porsche driver knocked a motorcyclist into a gully before swapping his licence plates in China.

Dashcam footage shows the yellow-plated Porsche attempting to overtake on a bend along the S206 Jiayu Line in Zhejiang when it hit a motorbike, sending the rider hurtling into a roadside gully.

The reckless driver, identified as Zhou, was initially seen walking towards the injured biker but abruptly turned back to his vehicle, removed the fake yellow plate, and replaced it with his legitimate blue Zhejiang B registration.

The motorcyclist, named He, was later diagnosed with a broken left arm on May 2.

Authorities confirmed that Zhou had been driving without a valid plate and was attempting an illegal overtake at the time of the collision.

The Yuyao Public Security Bureau confirmed Zhou's detention on Monday for dangerous driving.

The case remains under investigation.