ANC president Jacob Zuma will not step aside as the ANC presidential candidate because he believes that if he were to do that it would be like pleading guilty to the charges against him.

Addressing thousands of ANC supporters who gathered outside the Pietermaritzburg High Court during his court appearance on Wednesday, Zuma said stepping a side would also create a bad precedent.

"What has happened to me is that certain people have thrown this dark cloud to me with the aim of demonising me. So if I step aside, a bad precedent will be created. People will know that if you hate somebody, you just throw a dark cloud and it is the end of the story."

Zuma said President Kgalema Motlanthe was also becoming a victim of people wanting to make him look like a bad person.

"I am not going to step aside simply because I have not been found guilty by any court of law. I respect the Constitution and I understand it," said Zuma.

Earlier, ANC General Secretary Gwede Mantashe said Zuma's court case had gone from being prosecution to persecution.

"This is not only about Zuma but about the ANC. They want to prevent the ANC president from becoming the president of this country. The want to destroy the head... because they know that if you destroy the head, you destroy the body."

If the ANC's leader was destroyed, the party would struggle to survive in the long run, he said.

"The attack will also spread to all of us. That is the reason why we have appointed our own legal council to represent our interests in the case."

The ANC election front-runner faces charges of corruption, fraud, money laundering and racketeering.

The criminal charges against Zuma were reinstated after the Supreme Court of Appeal ruled in favour of an appeal by the National Director of Public Prosecutions (NDPP).

The NDPP had challenged a ruling made last year by Pietermaritzburg High Court Judge Chris Nicholson, which held that the charges against Zuma were invalid.