JOHANNESBURG - Members of Black First Land First turned up outside the Randburg magistrate's court to support Duduzane Zuma.
Zuma appeared to face two counts of culpable homicide.
The charges are in connection with a 2014 crash when he collided with a taxi after losing control of his car.
Zimbabwean national Phumzile Dube was killed on the scene while another passenger Nanki Mashaba died a few weeks later.
The BLF members confronted AfriForum's Kallie Kriel, saying the case against Zuma is a vendetta.
AfriForum's private prosecution unit is hoping to secure a culpable homicide conviction.
Advocate Gerrie Nel, who is leading the team, said in October last year that they are assisting the Dube family.
Meanwhile, BLF leader Andile Mngxitama called Kriel a racist shortly after Zuma's appearance.
He then accused journalists of allegedly assaulting one of his fellow BLF members.