ANC president Jacob Zuma's bid for the South African presidency is a party position and not his personal preference, the ruling party said on Thursday.

"The ANC wishes to reiterate, once again, that Jacob Zuma is the ANC's candidate for President of the Republic in the forthcoming national elections," it said in a statement.

"The ANC wishes to make it clear that Zuma was not expressing any personal preference when he spoke on this matter in Pietermaritzburg. He was articulating the position of the ANC, as it is his responsibility to do."

The African National Congress was responding to headlines indicating Zuma's refusal to step down as ruling party president, and in all likelihood, South Africa's next president.

"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," he said on Wednesday outside the Pietermaritzburg High Court.

He faces charges of corruption, fraud, money laundering and racketeering.

"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.

ANC spokesman Carl Niehaus said Zuma was nominated and elected president of the party and was the party's candidate for president of the country. This was a "simple fact" and "should not come as a surprise".

"The ANC therefore finds it strange that many media institutions have sought to present the statement of this fact as a sensational revelation."

The party added that it will not withdraw Zuma's candidature on the basis of allegations untested in a court of law.

It reiterated its belief in the constitutional principle of presumption of innocence which "requires that a person not be prejudiced or be considered 'tainted' simply because charges have been brought."

The ANC said the charges against its president were being used to "undermine the decision" of its membership but it would "not submit to such blackmail".

"Just as it observes the rule of law and the independence of the judiciary, the ANC will continue to observe the principles of the presumption of innocence and equality before the law.

"It calls on all political parties, media houses and commentators to do the same," the statement concluded.