President Mbeki will not refer any new cases to the Heath Special Investigating Unit and has said future investigations will be better handled by ad hoc commissions of inquiry.

Mbeki sounded the death knell for Judge Willem Heath and his unit's corruption-busting days during a brief media conference to announce changes to his cabinet and deputy ministers in Pretoria on Wednesday.

Quizzed on the continuing Heath saga, Mbeki said he would not refer any new cases to the "overworked" unit.

"I think if there is any new work, the most rational thing would be not to take a unit that is sitting on 200 000 cases but to appoint another unit to attend to a particular matter. It is not something we have discussed (but) that would be my feeling. I don't think it makes sense to give new work to a unit that is already overworked."

Mbeki went even further, saying he believed future investigations would be better handled by once-off commissions of inquiry.

"I think if there was a need to investigate something it would be wiser to do what the law empowers - set up ad hoc units to investigate particular things and when the work is done the thing ceases to exist. That's the direction I would go."

Mbeki said he remained convinced the organograms were part of Judge Heath's documents and those named in them would be targeted for investigation, despite claims by an investigative journalist that he drew up the diagrams and assurances by Judge Heath that he had never seen them before.

Mbeki, former president Nelson Mandela and other senior members of the government are listed in the organograms.

With acknowledgement to Marco Granelli and Independent