A passenger was repeatedly punched in an "inexcusable" road rage attack at a set of traffic lights in Fyshwick on Wednesday, police say.

The attack occurred at the intersection of Newcastle and Gladstone Streets, just opposite McDonalds, about 8.35am.

Police say a passenger of a silver Mercedes Benz got out of his car and walked up to a white Ford wagon, which was stationary nearby.

The man allegedly opened the door of the wagon and punched the driver several times.

He then walked back to the Mercedes and was driven from the scene by a woman with blonde hair.

The attack has drawn strong condemnation from ACT Policing, who say violent conduct has "no place on our roads".

"Violence on our roads is inexcusable,” Traffic Operations acting Superintendent Rod Anderson said.

"We all need to share the road, and drive patiently with consideration for all road users."

The alleged attacker is described as Pacific Islander in appearance, between 167cm and 177cm tall, with short dark-brown hair. He is thought to be about 30-years-old.

Anyone with information should contact Crime Stoppers on 1800 333 000 or via the website.