Cape Town — The bitter confrontation between structures of the South African government and the ruling party appeared set to intensify on Thursday as President Thabo Mbeki's cabinet rejected a judge's finding that Mbeki and his ministers had interfered in a major prosecution.

The dispute, centred on President Thabo Mbeki and his prospective successor, Jacob Zuma, could see Mbeki forced out of office six months before his term expires.

Last week a judge declared as invalid a decision to charge Zuma with corruption, saying he should have been given the opportunity to make representations as to why he should not be charged.

In a further finding which has set off a political firestorm, the judge, Chris Nicholson, suggested that successive ministers of justice, Mbeki and his whole cabinet should be held accountable for interfering in the prosecution.

Mbeki fired Zuma as deputy president of the country in 2005, after Zuma's financial adviser had been jailed for corruption in a case in which Zuma was named.

However, Zuma completed a successful political comeback last December, when he displaced Mbeki as party leader and became the party's choice to replace Mbeki as president of South Africa at the end of his second and final five-year term next year.

Only days after Zuma defeated Mbeki, prosecutors revived charges against him. It was this decision the judge overturned last week.

On Wednesday, the National Prosecuting Authority (NPA) announced that it was appealing against the judgement, prompting an angry response from the ANC.

On the same day, Mbeki's cabinet was discussing the matter at its regular weekly meeting.

On Thursday, government communications officers released a statement from the meeting in which the cabinet said the judge's "untested inference" that there had been political interference with prosecutions was "untrue, unfounded and does not hold water."

The statement added: "Cabinet has decided to seek legal advice on the inferences made by Judge Nicholson that President Thabo Mbeki and the executive interfered with the NPA regarding the decision to prosecute Mr Jacob Zuma."

With the legal ramifications of the case likely to take months, even years, to unfold, the latest developments augur badly for Mbeki's survival as president. Even before the cabinet's position was announced, Johannesburg's Business Day reported that key party leaders would press in the coming days for his resignation.