Johannesburg - Prosecutors in South Africa said Wednesday they would seek leave to appeal a court's ruling last week that corruption and fraud charges against African National Congress (ANC) leader Jacob Zuma were invalid.

The National Prosecuting Authority's (NPA) refusal to drop the case against Zuma is likely to add to tensions between supporters of Zuma and arch-rival President Thabo Mbeki.

Zuma is expected to take over from Mbeki as president after general elections in April that the ANC is expected to easily win.

Zuma's supporters have been calling for Mbeki to step aside or for the ANC to recall him ahead of the elections after the Pietermaritzburg High Court last week found there had been political interference in the decision to prosecute Zuma.

The court set aside all charges against Zuma after he successfully argued that his rights had been trampled by not being allowed to make representations about the charges facing him before being indicted.

Announcing the decision to seek leave to appeal, NPA spokesman Tlali Tlali said the "court's interpretation of the constitution and of the NPA Act was not a correct way" and that the court ruling on political interference "could have serious consequences" for NPA operations.

Zuma's allies have long claimed the charges were a plot by his detractors, including Mbeki, to bar him from becoming president.

The charges stemmed from his relationship with fraudster Schabir Shaik, who was sentenced to 15 years in prison in 2005 for corruption in a 1990s state arms deal.

Some ANC members have warned of bloodshed if Zuma is brought to trial. (dpa)