The Democratic Alliance (DA) filed papers at the High Court in Pretoria on Friday opposing the appointment of prosecutions boss Menzi Simelane.
Speaking outside the High Court in Pretoria after filing papers to oust Simelane, DA leader Helen Zille said: "We believe advocate Simelane is not a fit and proper person. He does not believe in the independence of the judiciary, it will merely become an extension of the African National Congress (ANC)".
In the founding affidavit, chairperson of the DA James Selfe said that the party challenged Simelane's appointment as it was an objective jurisdictional requirement that he must be a "fit and proper person" and have "experience, conscientiousness and integrity".
They also challenged President Jacob Zuma saying that his decision was not administrative but an executive action.
"It was unlawful, irrational, arbitrary, biased, based on an ulterior motive and inconsistent with the constitution."
The matter will be heard in April.