Lt-Col Andre Traut said the man, in his 20s, was driving along Govan Mbeki road around 1pm when he was forced off the road by another taxi.
He got out of the vehicle and was shot in the road. The group who shot at him fled in the direction of Philippi East.
The provincial flying squad arrested two men, aged 40 and 50, shortly after and confiscated two firearms. Traut said more people were believed to have been responsible and the investigation was continuing.
The motive for the shooting was not known.