ANC president Jacob Zuma on Tuesday filed his replying heads of argument with the Supreme Court of Appeal in Bloemfontein in the National Prosecuting Authority's appeal application.

The Bloemfontein court would on Friday hear an appeal by the National Director of Public Prosecutions against a Pietermaritzburg High Court judgment which invalidated the charges it brought against Zuma.

Judge Chris Nicholson granted the state leave to appeal against his 12 September judgment. He held that the State's decision to prosecute Zuma was unlawful because it had failed to take representations from him.

Zuma faced a charge each of racketeering and money laundering, two charges of corruption and 12 charges of fraud related to the multi-billion rand government arms deal.

He was charged in 2005, but the case was struck from the roll in 2006. He was recharged in December 2007.

Lawyers for former state president Thabo Mbeki would also address the Supreme Court of Appeal during the hearing.

Earlier, Mbeki unsuccessfully challenged Nicholson's judgment, which inferred he politically meddled in the National Prosecuting Authority's investigation of Zuma. The Constitutional Court dismissed Mbeki's application, saying it was "not in the interests of justice" to hear it at that stage.

Mbeki turned to the SCA which granted him time to address the panel of five appeal judges who would sit on the appeal.

The SCA panel would include the court's acting Deputy President Judge Louis Harms, Judge Ian Farlam, Judge Nathan Ponnan, Judge Mandisa Maya and Judge Azar Cachalia.

Court officials said security at the SCA would be very tight. A huge media contingent was also expected in Bloemfontein.

Free State ANC spokesperson Teboho Sikisi said the party had applied for permission to hold a rally in front of the court on Friday.

"Something along the lines of what happened during the last court appearance," he said.

Sikisi said they expected all the national leaders of the alliance partners to be at the court.

Sapa