A South African court on Thursday put off judgment on whether ANC leader Jacob Zuma can prevent seized documents being used against him as evidence at a corruption trial that could stop him becoming president.

After a three-day Constitutional Court session, Chief Justice Pius Langa gave the defence and state more time to submit arguments on warrants used in the seizures.

"We reserve judgment on this matter," he said.

Langa said Zuma would have to submit a written argument within a week and the state was required to respond by March 27. A final ruling on the case could still take weeks or months.

Zuma, who defeated President Thabo Mbeki for the leadership of the ruling African National Congress in December, is accused of accepting hundreds of thousands of dollars in bribes from French arms manufacturer Thint and his former financial adviser.

The trial for corruption, money-laundering, fraud and racketeering is due to start in August and is likely to decide whether Zuma succeeds Mbeki when the latter has to step down in 2009. Zuma has said he will bow out if convicted.

Zuma and Thint say the documents were unlawfully obtained.

The prospect of several delays leaves a question mark over whether Zuma's legal battles will drag into the presidential election period and cloud South Africa's political future.

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.

Zuma's lawyers argued the warrants used in raids were too vague and violated their privacy, property and other rights guaranteed under South Africa's constitution.

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.