President Jacob Zuma said on Wednesday that reports that he was bound by an undertaking not to appoint a successor to axed National Prosecutions boss Vusi Pikoli were false.

Zuma said it was incorrect that former President Kgalema Motlanthe had agreed to wait until the High Court in Pretoria ruled on Pikoli's legal challenge to his dismissal, to appoint a new National Director of Public Prosecutions.

Motlanthe had merely undertaken to give Pikoli's lawyers notice should he move to fill the post, the Presidency said in a statement.

Pikoli was suspended by former president Thabo Mbeki in September 2007, and finally fired by Motlanthe in December last year for being insensitive to issues of national security.

Zuma also said media reports that Mbeki had told the court he was advised by the National Security Council to suspend Pikoli were false.

"All he said was that he conferred with the National Security Council," the Presidency said.

Pikoli insists that he was fired for political reasons, including his decision to prosecute Zuma and suspended national Police Commissioner Jackie Selebi for corruption.