Zuma later in the day faces a vote on the motion of no confidence in Parliament.
The group of around 200 ANC supporters sang Struggle songs and chanted “Zuma must stay” as they prepared to make their way to Parliament.
A march by opposition parties and civil society was taking place on the other side of town and also making its way to Parliament amid a heavy police presence.
On Monday, Speaker Baleka Mbete announced her decision to allow a secret ballot in the vote on the motion of no confidence in Zuma.