Democratic Alliance leader Helen Zille filed an urgent application to the High Court in Pretoria on Tuesday requesting a review of the National Prosecuting Authority's decision to drop charges against ANC president Jacob Zuma.

After spending around 40 minutes inside the court, Zille, dressed all in black, spoke to the media around 10am.

Zille said the decision announced by acting National Director of Public Prosecutions (NDPP) Mokotedi Mpshe was unlawful and irrational.

Helen Zille bites back

"It violated the Constitution, it violated the law and it violated the NDPP's own policy.

"It is an irrational decision, it is an unlawful decision and the reasons given do not hold water because they do not address the question of the merits of the case against Jacob Zuma."

On Monday Mpshe withdrew corruption charges against Zuma saying the decision was based on flaws in the prosecution's own process. The merits of Zuma's case were not taken into consideration.

The withdrawal was primarily because there had been an abuse of process by the former head of the Directorate of Special Operations (DSO), Leonard McCarthy and former National Prosecuting Authority boss Bulelani Ngcuka.

The charges were formally withdrawn in the High Court in Durban on Tuesday morning.