Former deputy president Jacob Zuma has been barred from consulting former judge Willem Heath. If he does contact him, he will be in breach of his bail conditions and could be jailed.

Heath, former head of the Special Investigating Unit into the arms deal, was added to prosecutor Anton Steynberg's comprehensive list of state witnesses late on Wednesday. When Steynberg handed in the initial list to the court, he said it was a condition of Zuma's bail that he would not be allowed to contact any of them.

Last night Heath told the Cape Times he was not aware that his name had been added to the list of state witnesses. He denounced the move as a ruse by the prosecution and said he would continue to consult Zuma.

"I was briefed by Zuma before that list was drawn up. They're not entitled to stop Zuma from consulting me," he said.

"Of course it's a ruse. When a witness is cited or subpoenaed and there's a fear that the accused will interfere or intimidate the witness, the court will order the accused not to contact the witness. None of these (concerns) were present in this instance."

Heath's announcement on Sunday that he had been briefed by an independent firm of Cape Town attorneys to serve as a consultant in Zuma's proposed battle with the National Prosecuting Authority has triggered shockwaves throughout the South African legal community.

Last night, a very senior member of one of the country's law societies said: "There can be no doubt that Heath is out of order.

There is a clear conflict of interests. On the one hand if he is a witness for the state, he can't be advising the defence. On the other hand, if Zuma's bail conditions preclude him from speaking to state witnesses, it doesn't matter who Heath was briefed by, the bail conditions are a total bar on Zuma speaking to Heath."

A senior member of the judiciary said Heath's decision had plunged the country into virgin legal territory in relation to the conflict of interests question.

"Heath obviously has information that he gathered during his time as an investigating judge, but that information has been led as evidence, so unless he perjures himself, there is no conflict of interests there, but if he claims inside information this could be advantageous to the defence."

With acknowledgements to Estelle Ellis, Kevin Ritchie and the Cape Times.