An appeal court is to decide whether Jacob Zuma, the leader of South Africa’s governing ANC, should be recharged with corruption and fraud.
Judges are to decide if an earlier high court ruling dismissing charges against Mr Zuma was correct.
If the judgement goes in favour of the state prosecutors, the case against Mr Zuma could be reinstated.
The ANC leader is widely tipped to become the country’s next president after upcoming elections.
Whatever happens in the Bloemfontein appeal court on Monday, Mr Zuma will remain the ANC’s contender to run the country after the forthcoming general election, says the BBC’s Southern Africa correspondent Peter Biles.
The 65-year-old has always denied charges of graft, money-laundering and racketeering, stemming from a controversial $5bn 1999 arms deal.
He has said he would only resign from public office if convicted.
Charges of corruption, fraud, racketeering and money laundering against Mr Zuma were dismissed on a technicality last September.
Judge Chris Nicholson also inferred there may have been political interference in the prosecution of Mr Zuma.
That led Thabo Mbeki to stand down as president and his replacement by Kgalema Motlanthe, an ally of the ANC leader.
Mr Motlanthe has said Mr Zuma would lead the ANC into this year’s elections even if he was charged with corruption.
“So as far as the ANC is concerned, if the Nicholson judgement is overturned, whatever happens thereafter must run its course, even if he is charged,” Mr Motlanthe told South Africa’s Mail and Guardian newspaper last week.
Mr Zuma’s supporters say the charges were part of a plot to prevent him becoming president.
For several years, the shadow of corruption has been hanging over Mr Zuma, who won a bitter ANC leadership contest against Mr Mbeki last year.
In 2005, Mr Zuma was sacked as South Africa’s deputy president when his financial adviser, Schabir Shaik, was found guilty of soliciting a bribe on behalf of Mr Zuma and jailed for 15 years in connection with the arms deal.
Mr Zuma then went on trial, but that case collapsed in 2006 when the prosecution said it was not ready to proceed.
He was also charged with rape, but acquitted in 2006.