Court papers are expected to be filed shortly to prevent the appointment of a permanent successor to axed National Prosecuting Authority (NPA) boss Vusi Pikoli, his lawyers said on Wednesday.

An urgent application for an interim interdict would be filed in the High Court in Pretoria "within a few days", Pikoli's lawyer Aslam Moosajee said.

"We are in the process of settling papers."

Earlier, Business Day reported that the Presidency had informed Pikoli that a permanent successor would be appointed, despite Pikoli challenging his dismissal in court.

Pikoli on Tuesday said he had received notice of the impending appointment. He had argued that he was suspended by former President Thabo Mbeki to protect suspended police chief Jackie Selebi from an investigation.

After former President Kgalema Motlanthe fired him last year, Pikoli claimed it was because the African National Congress wanted a more amenable prosecutions head. Zuma was then facing charges of fraud and corruption.

Pikoli had written to Judge President Bernard Ngoepe of the High Court in Pretoria, asking for a court date for his case in which he was challenging his dismissal on the grounds that it was unconstitutional and "flawed", Business Day reported.

Zuma's acting spokesperson Vincent Magwenya said: "I can't comment until all processes relating to this matter are finalised."

The Democratic Alliance said Zuma should not proceed with the appointment of a permanent successor.

"Firstly, because advocate Vusi Pikoli's dismissal may well be set aside by the courts," said the party's "shadow" justice minister Dene Smuts.

A second reason, was that two new proposals for an appointment mechanism should be considered.

When Kgalema Motlanthe was President he suggested the appointment of the National Director of Public Prosecutions (NDPP) should not remain solely in the hands of the President.

"He proposed that the process could be depoliticised by requiring the Judicial Service Commission to select candidates for the President's consideration."

Smuts said the Parliamentary ad hoc committee that sat on the Ginwala inquiry had found that "it is anomalous that Parliament plays no role in appointing the NDPP, while it has the final say in his or her removal.

"The wisdom of these proposals is underscored by the unseemly haste with which the Presidency seems to wish to proceed on a new appointment."