A senior South African minister said he did not believe conspiracy allegations against three top black businessmen but said they did not reflect any paranoia by President Thabo Mbeki.
Mr Essop Pahad, minister in the office of the presidency, said in London that the three men - Mr Cyril Ramaphosa, Mr Tokyo Sexwale and Mr Mathews Phosa - were steeped in the democratic culture of the ruling African National Congress.
"I don't think that Cyril or Tokyo or Mathews would get involved in an attempt which would lead to physical harm of the president," Mr Pahad told reporters.
Safety and Security Minister Mr Steve Tshwete said on Tuesday that a former official with the ANC had produced evidence of a plot to oust Mr Mbeki as ANC leader and police had launched an inquiry.
Leading analysts have dismissed the claims as fabrications to discredit Mr Mbeki's potential challengers for leadership of the ANC ahead of a party congress next year.
Mr Pahad, one of Mr Mbeki's oldest and closest friends, defended the Mr Mbeki."He [Mbeki] is not paranoid about anything. He's certainly not paranoid about having to face anybody in an election," he said.
Mr Pahad said the police inquiry followed weeks of rumours within the ANC and did not assume the guilt of any of the three men, who all hold or have held top positions in the ANC.