Police say a black Lexus and a red Holden were travelling southbound on Gungahlin Drive when they stopped at the intersection of Kosciuszko Avenue and The Valley Avenue, just before 10am Friday.

Police allege the two men engaged in a confrontation and one of the men allegedly assaulted the other.

Police believe there were a number of other vehicles on the road at the time of the incident, and are calling on anyone who witnesses the incident to come forward.

Anyone with information or dash-cam footage that could assist police is urged to contact Crime Stoppers on 1800 333 000, or via the Crime Stoppers ACT website and quote reference 6682488.