Members of the government have effectively been banned from making public comments on the Scorpions' investigation of Deputy President Jacob Zuma.

Speaking in Soweto yesterday, Minister of Justice Penuell Maduna said that "with the support of President Thabo Mbeki, we have decided not to comment on this matter".

"No one must comment. We are not in the business of running investigations through the media."

National Director of Public Prosecutions Bulelani Ngcuka, standing beside Maduna, appealed to the media to give the Scorpions "space" to conduct their investigation.

"We will call you when the time is appropriate," he said.

The Scorpions are investigating aspects of Zuma's dealings with his financial adviser, Schabir Shaik, and a French firm awarded an arms contract.

Maduna's comments, made at the opening of the Nthabiseng Thuthuzela care centre at Baragwanath Hospital yesterday, came just days after Zuma insisted that suspicions about his dealings were "baseless, defamatory and grossly unfair" and complained of a "trial by media".

Maduna's spokesman, Paul Setsetse, said later yesterday a decision had been made that the government should not comment until the investigation had been completed so the due process of law could take its course.

"This is a matter between the deputy president and the prosecuting authority ... and as far as government is concerned, we will not be commenting any further until the investigation has been concluded," said Setsetse.

Well-placed government sources said the decision not to comment was an attempt "not to fuel the fire" - a reference to the public debate.

The presidency was not available for comment.

Meanwhile, Democratic Alliance spokesman Hendrik Schmidt has welcomed ANC member and businessman Cyril Ramaphosa's conclusion that there is no role for him to play in relation to the investigation "as all mechanisms ... are in place".

Schmidt demanded, however, that Mbeki investigate and discipline those in the ANC who had "instigated" Ramaphosa's being drawn into the matter.

"President Mbeki needs to reassure the public that he is not involved in this inappropriate political interference and that, as president of South Africa, he is prepared to stand up for the independence and integrity of the National Prosecuting Authority."

With acknowledgements to Jeremy Michaels, Sapa and the Cape Times.