Khoi and San leaders say the fact that they were not invited to form part of the National Convention starting on Friday shows that they are still not recognised by the South African government.
The two-day Convention at the University of South Africa's Unisa main campus in Pretoria is meant to kick-start the National Dialogue process.
The process leading up to the gathering has been marred by controversies that include the hefty price tag of the dialogue and the withdrawal of legacy foundations.