Justice Minister Jeff Radebe said yesterday he was investigating remarks made by Heath in an interview last week and hoped to report back to the president in the next few days.

Heath told City Press last week that former president Thabo Mbeki had engineered rape and corruption charges against Zuma. This prompted an angry response from Mbeki, who denied the "grave" claims.

In an interview with Ukhozi FM on Wednesday, Zuma strongly denied having close ties to Heath. The former judge acted as Zuma's legal adviser when the president faced a rape charge and, later, when he was charged with corruption.

"When you hire a lawyer it doesn't mean that he is your friend ... sometimes you hire a lawyer to represent you and the next day you find him standing on the other side. That's how lawyers operate, they serve whoever comes first and requests help," said Zuma.

The president distanced himself from Heath's claims that Mbeki had instigated the criminal cases that threatened to end Zuma's political career.

"He is not aligned to me ... I want to deny that ... he has his own views. He holds his own views on what happened, you know that he was always involved in the investigations field even before.

"It may well be that there are some things that he knows that we don't. That is why I'm saying that his comments ... have made us to look into them because we have to satisfy ourselves that if he holds such views and such emotions ... given the sensitive job that he has been given, if he will be able to work properly," said Zuma.

"Because of the position he is appointed to, it is crucial for the nation to be assured that he holds no grudges and that he will do his job properly," said Zuma.

Radebe yesterday said that he and Department of Justice director-general Nonkululeko Sindane had met Heath on Tuesday "to obtain information ... in order to fully understand" the circumstances under which the interview took place.

"Advocate Heath undertook to provide me with relevant information on this matter and has recently handed over information to my office on this matter for consideration," said Radebe.

"At the outset he strongly indicated that the interview was conducted in his personal capacity and not in his professional capacity as the head of the SIU."

Presidential spokesman Mac Maharaj told the Sunday Times on Friday that Zuma's office was in touch with Mbeki's office following a formal complaint from the former president.

Heath's comments have also irked Bulelani Ngcuka, the former National Director of Public Prosecutions.

In today's Sunday Times, Ngcuka addresses an "open letter" to Heath, saying that the allegations made were "very serious".

"Evidence of such conduct as you allege on my part would result in a criminal conviction. One therefore wonders why, if you have such evidence, you have not seen it fit to formally lay charges against me in all these years.

"The reason, in my considered view, is that these allegations are as false as they are disingenuous," writes Ngcuka, who describes Heath as a man driven by bitterness.

"One however understands that a man so bitter at being 'excluded' from office and being rendered a pauper as a result of such 'exclusion' would be blind to the facts and be inclined to lash out at all those who he misguidedly perceives to have conspired to his prejudice," he writes.

Heath had to quit his job as head of the SIU in 2000 after the Constitutional Court ruled that a sitting judge could not head up such a unit.

He then applied to Mbeki for early retirement but the former president turned him down, and he lost lucrative benefits such as a salary for life.