The Ahmed Kathrada Foundation says former president Jacob Zuma, a "constitutional delinquent", is not suitable for Parliament.
On Sunday, the non-profit organisation was accepted as friends of the court in the case that the Electoral Commission of South Africa (IEC) lodged in the Constitutional Court after the Electoral Court dismissed its disqualification of Zuma from contesting for Parliament.
The IEC had disqualified Zuma on the grounds that he had a criminal record after he was found guilty and convicted of disobeying a Constitutional Court order to appear and testify before the Zondo Commission.