A South African court has granted the state permission to use documents from Mauritius in a possible new graft case against the ex-deputy president.
Mr Zuma is still deputy president of the ANC
Last year, a corruption trial against Jacob Zuma collapsed because the prosecution said it was not ready.
Mr Zuma, sacked two years ago as deputy president in connection with an arms deal, has appealed against the ruling.
But observers say the decision is a blow for his ambitions to become the ruling party's presidential candidate.
Mr Zuma, who is still deputy leader of the African National Congress (ANC), is a candidate to succeed President Thabo Mbeki as its presidential candidate.
The party is due to decide who to support in the 2009 elections at a conference in December this year.
The prosecution can now go ahead and get 14 documents which allegedly contain information about payments offered to Mr Zuma by the French arms company, Thint.
Both the company and Mr Zuma have appealed against the decision by the Durban High Court.
The outcome of the appeal is expected in September.
A National Prosecuting Authority spokesman said the papers would allow the director of public prosecutions to decide whether to proceed with a new trial against Mr Zuma.
"We have never taken any decision to recharge the ANC deputy president," South Africa's Mail & Guardian newspaper quotes Panyaza Lesufi as saying.
Mr Zuma was sacked from the government two years ago when his financial adviser Schabir Shaik was found guilty of corruption in a case that arose from a government arms procurement deal in the 1990s.
Last year, Mr Zuma was acquitted in a separate trial of raping the daughter of a family friend.
He has always maintained that the cases were aimed at sidelining him politically.
The former head of the ANC's military wing, Mr Zuma still has considerable support from the influential leaders within trade unions and the Communist Party.
He is seen as less aloof than Mr Mbeki and likely to drop some of the ANC's more conservative economic policies.