A KwaZulu-Natal policeman shot his off-duty colleague and then himself following a collision on Monday morning in what police believe was a case of road rage.

Police spokesperson Superintendent Zandra Wiid said the incident involving the police car and the private vehicle took place at 6am in the town of Harding, which is midway between Port Shepstone and Kokstad.

Wiid said the two policemen collided at an intersection in Harding.

An argument between the two constables, who both worked at the Harding police station, ensued.

The policeman who was on duty then pulled out his service pistol and shot his colleague before turning the gun on himself.

Wiid said the matter was being investigated and the officers' names could not be released until the next of kin had been informed of their deaths.

Sapa