An EFF MP was stopped from asking Cyril Ramaphosa about his role in Marikana.
It's not clear what Shabangu was told about the Marikana violence in the days ahead of the shooting.
Former Mineral Resources Minister Susan Shabangu is testifying at the Farlam Commission of Inquiry.
The inquiry will determine whether the state must reinstitute charges against 279 miners.
Miners say Deputy President Cyril Ramaphosa must take responsibility for the Marikana massacre.
Economic Freedom Fighters (EFF) leader Julius Malema is expected to attend the rally.