Johannesburg - South Africa's ruling African National Congress leader Jacob Zuma was due to hear Friday whether his attempt to have the corruption charges that threaten to mar his path to the presidency quashed has been successful.

Pietermaritzburg High Court is due to rule on an application by Zuma to have his case for alleged corruption, fraud and racketeering thrown out of court on the basis that prosecutors did not follow proper procedure in indicting him.

The ANC and its ruling alliance partners in the trade union movement and Commmunist Party have been calling for the charges to be dropped, saying the case is merely a ploy to bar the controversial Zuma becoming president.

"Our hopes are high that the charges would be thrown out," ANC spokeswoman Jessie Duarte said outside the courtroom, where thousands of Zuma supporters had gathered in a mass display of support.

Security is tight for the ruling following threats of violence from some of Zuma's youth supporters in the event of the ruling going against him. The ANC leadership has however vowed to respect the court's decision.

Thursday's night vigil by a thin scattering of supporters in a central square had however passed off without incident.

Earlier this week, a pro-Zuma protest in nearby Durban turned violent when thousands of demonstrators, many armed with clubs, burned a flag with the name of the special crime-fighting unit that investigated Zuma, looted shops and threw stones at police.

Zuma is the ANC's candidate to replace President Thabo Mbeki, when his second term expires at next April's elections.

The charges stem mainly from his relationship with convicted fraudster, Schabir Shaik. Shaik was convicted, among other things, of soliciting an annual bribe from a French arms manufacturer on Zuma's behalf.

A first corruption case against Zuma was thrown out of the same Pietermaritzburg court in 2005 over delays by the prosecution in presenting evidence.

Prosecutors brought new expanded charges in December 2007, days after he romped to victory in Mbeki in an ANC leadership race. (dpa)