Former president Jacob Zuma has been forced to eat humble pie after his bid for private prosecution of his predecessor was rejected by the South Gauteng High Court.

A full bench of the court set Zuma's application aside, saying it had been brought to the court with an ulterior motive.

Zuma was accusing President Cyril Ramaphosa of being an accessory to a crime in the alleged leaking of Zuma's medical records by prosecutor advocate Billy Downer.

Zuma had already failed to get the court to allow him to prosecute Downer and journalist Karyn Maughan in the same matter.

The court also found that the private prosecution certificates granted to Zuma by the NPA did not apply to Ramaphosa and declared Zuma's application to be unlawful and unconstitutional.

At the heart of Zuma's and advocate Dali Mpofu's argument is that Ramaphosa failed to launch an investigation into Downer's actions.

The Presidency said Ramaphosa welcomed the judgment.

"The President has always maintained that Mr Zuma's private prosecution constituted an abuse of court processes and that it was unlawful and unconstitutional."