South Africa's state prosecutor said on Monday he would appeal against a High Court ruling which could lead to 783 corruption charges being reinstated against President Jacob Zuma.
The decision will bring some relief to Zuma as he faces mounting calls to quit from the opposition and even from members of the ruling African National Congress after a damning constitutional court judgment against him in March.
The main opposition party stepped up its criticism on Monday, saying the state prosecutor's decision was an attempt to shield the president and buy him time before elections in August.
A decision by the National Prosecuting Authority (NPA) in April 2009 set aside hundreds of charges allowed Zuma to run for president the same month.
The NPA's decision at the time was based on phone intercepts presented by Zuma's legal team that suggested the timing of the charges in late 2007 may have been part of a political plot against Zuma.
But the High Court last month ordered a review of the NPA's decision to drop the charges, terming it "irrational".
"I have decided to apply for leave to appeal against the judgment," the National Director of Public Prosecutions Shaun Abrahams told a televised media conference in the capital.
"I will always do what is correct, irrespective of whether the individual is an ordinary person, a Cabinet minister or a sitting president."
Abrahams said the law allowed the prosecutor a discretion that can be exercised at various stages of the an investigation, and that the court ruling could dilute the NPA's powers.
"It is also a matter that seriously affects the separation of powers. This is an important matter of principle which affects all prosecutions, it is so important. I believe it needs the decision of an appeal court," Abrahams said.
The hundreds of corruption charges relate to a major government arms deal arranged in the late 1990s.
Zuma said last month that an investigation into the deal had found no evidence of corruption or fraud. Critics denounced the findings as a cover-up and said they would continue to campaign for justice.
The opposition Democratic Alliance party said in a statement that Abrahams' decision was "a blatant delaying tactic to shield Jacob Zuma from facing the 783 charges of corruption, fraud and racketeering leveled against him almost a decade ago."
ANC spokesman Zizi Kodwa said the NPA had taken its decision independently.
Analysts said Abrahams' decision was a reprieve for Zuma, because the appeal process could take several months.
"The unambiguous politically effect is that it will embolden Zuma. The decision undoubtedly gives Zuma another day, another month, another year to breathe," Susan Booysen, a political analyst at South Africa's University of the Witwatersrand.
"The effect for South Africa, is that the trauma is continuing in this never-ending saga."
Zuma is beset with scandals in the run-up to local elections in August where his party faces a strong challenge from opponents seeking to capitalize on what they see as his economic and political missteps.
The president survived an impeachment vote last month called after the Constitutional Court said he breached the law by ignoring an order to repay some state funds spent on renovating his home.
In December he was widely criticised for changing his finance minister twice in a week, sending the rand plummeting and alarming investors.
(Additional reporting and writing by James Macharia; Editing by Andrew Heavens)