Former South African President Jacob Zuma is pursuing private prosecution proceedings to remove the lead prosecutor in an arms deal corruption trial after failed legal challenges, his foundation said on Sunday.

Last month the Supreme Court of Appeal (SCA) torpedoed Zuma's latest bid to have lead prosecutor Billy Downer taken off the case after accusing him of bias and leaking of confidential information to a journalist in contravention of the national prosecution act, among other complaints.

The SCA dismissed the application for leave to appeal on the grounds that there is no reasonable prospect of success and there is no other compelling reason why an appeal should be heard.

The spokesman of the Jacob Zuma Foundation, Mzwanele Manyi told a press briefing that Zuma's instructions to his legal team to institute private prosecution "will now be put into operation in the next few days".

He also said Zuma's legal team has filed a reconsideration application to the president of the SCA, a petition to hear the appeal.

Zuma, who was ousted from the ruling African National Congress in 2018 after nearly two decades as president, has pleaded not guilty to charges of corruption, money laundering and racketeering in the long-running case over the $2 billion arms deal in the 1990s.

The deal case has dogged Zuma since he was sacked as deputy president of the country in 2005. He said he was the victim of a political witch-hunt.

On Monday the long-delayed trail is set to get underway and Zuma will be present in court.

Manyi said Zuma, who turns 80 on Tuesday, is applying for a postponement because "it is very clear that the conditions for a fair trail are non-existent".

On Monday his team will also respond to the supplementary affidavit served by the National Prosecution Authority where they seek to introduce new evidence in the trial.

"All His Excellency President Zuma really wants is his day in court, in a fair trial and certainly not in a forum which is being rigged by the State," Manyi said.