The DA has adopted stringent leadership campaign rules that prohibit candidates from running public campaigns in the media.
Friday's meeting of the DA's federal council also barred candidates from holding public debates in the run-up to the national conference next month, where the party will elect new leaders.
This comes as the race to lead the party heats up between incumbent John Steenhuisen and KwaZulu-Natal MPL Mbali Ntuli.
The new rules have been slammed by Ntuli's supporters, who say they perceive them as an attempt to curtail her campaign, which so far has been run very publicly and has featured media interviews, press conferences and a challenge to a public debate with Steenhuisen.
DA Western Cape leader Bonginkosi Madikizela confirmed the new rules, saying he supports them "120%".
Madikizela said the DA race is not to elect the president of SA but the leader of the DA and there is no reason for public debates. He said it is nonsense to say the rules target Ntuli.
"You can't burn the house down that you claim you want to save," said Madikizela in reference to Ntuli's campaign.