A South African state lawyer accused ANC leader Jacob Zuma in court on Wednesday of trying to delay justice through his attempt to block the use of seized documents at his upcoming corruption trial.

The trial, due to start in August, could ruin Zuma's hopes of succeeding President Thabo Mbeki in 2009. The head of the ruling African National Congress is accused of accepting hundreds of thousands of dollars in bribes over an arms deal.

On Tuesday, Zuma launched an application in the Constitutional Court for leave to appeal against prosecutors' searches and seizures of documents in 2005. It is not clear when the court will deliver its ruling.

Wim Trengrove, acting for the state, told the court that by making the application, Zuma was merely delaying justice.

"The place to do it is on the trial court," Trengrove said.

Trengrove said the state believed the case against Zuma could lead to a convinction.

"We are sure that we have a case, not merely a prima facie case, but a case with a reasonable prospect of conviction," Trengove was quoted as saying by SAPA news agency.

The trial for corruption, money-laundering, fraud and racketeering is likely to decide whether Zuma succeeds Mbeki when the latter has to step down. Zuma, who defeated Mbeki in a party leadership contest last December, has said he will bow out if convicted.

If the right to an appeal is granted, it will leave a question mark over whether Zuma's legal battles will drag into the presidential election period.

Zuma's rise has worried some investors, who fear that under his rule South Africa could shift away from Mbeki's pro-business policies. But the power struggle between the two men has also stirred concerns of instability.

Zuma says the charges against him are politically motivated.

South Africa's Supreme Court of Appeal ruled in November that documents seized by the elite Scorpions crime-fighting unit could be used against Zuma when he went to trial.

The appeal court also opened the way for South African prosecutors to use documents from Mauritius, said to contain evidence that bribes were solicited on behalf of Zuma in return for using his influence in a government arms deal.

Zuma is also appealing that ruling in the Constitutional Court and, in a separate case, is trying to block authorities in Mauritius from handing over documents for his trial.