DA leader Helen Zille reiterated her call for ANC president Jacob Zuma to have his day in court either to be acquitted or convicted, in her regular Friday letter.

Zille said the party would do everything to safeguard constitutional democracy, and that is why they filed an urgent application in the High Court in Pretoria to review the decision by the National Prosecuting Authority (NPA) to drop corruption charges against him.

"We will fight to the bitter-end, using all the legal measures available to us, to ensure that justice is served."

"Zuma must have his day in court. All other evidence in possession of the NPA that points to criminal conduct by [former Scorpions boss Leonard] McCarthy and [former NPA boss Bulelani] Ngcuka must be heard in court, too," she said.

She added the DA was the only party that can stop Zuma and his "ANC-clique" from abusing their power and undermining the Constitution.

"Zuma has not proven his innocence. He has not been acquitted. He has merely been let off the hook by the NPA," she said.

"Why would the NPA withdraw the case in April, just two weeks before a general election? The unseemly haste can only be politically motivated," said Zille.

She added that the withdrawal of the charges gave the ANC the election boost it needed, enabling it to falsely claim that Zuma has been vindicated, and indeed that he was innocent from the start.

On Monday National Director of Public Prosecutions Mokotedi 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 appeared to have been an abuse of process by McCarthy and Ngcuka.

The charges were formally withdrawn in the High Court in Durban on Tuesday morning.