President Thabo Mbeki is failing to lead the country by keeping silent on the scandal around Deputy President Jacob Zuma, the Democratic Alliance has charged.

The party's leader, Tony Leon, said in his weekly newsletter on Thursday that there was "a prima facie case of failure" against Mbeki.

"He bears direct responsibility for the corruption in the arms deal - not just as head of the government, the ruling party and the nation but as someone who was intimately involved in the decisions on procurement."

National director of public prosecutions, Bulelani Ngcuka, announced on Saturday that Zuma would not be prosecuted in connection with the multibillion-rand arms deal, despite indications that there could be a corruption case for him to answer.

Allegations, which Zuma has repeatedly rejected, are that he tried to solicit a R500 000 bribe from Alain Thetard, the former Southern African head of French arms company Thomson CSF.

Leon accused Mbeki of attempting to suppress any investigation into corruption in the arms deal. "If anything, the president has struggled vigorously against attempts to expose corruption in the arms deal."

Mbeki had taken any allegations of corruption in the deal as being cooked up by critics of the government, Leon said. He added that Mbeki seemed incapable of distinguishing between the national interest and party interest.

The people of South Africa would find the president guilty unless he provided a satisfactory answer to the "prima facie evidence of his failure. Only one answer will suffice: the president must demand that the deputy president step down".

United Democratic Movement leader Bantu Holomisa echoed Leon's sentiments while addressing students at the University of the North West in Mafikeng on Thursday.

He said Mbeki had to put South Africa above his party and his deputy.

The ANC has responded to media reports that it owned Floryn Investments, via its nominee Schabir Shaik, and that Floryn in turn owned 10 percent of Nkobi Holdings - a company that benefited from the arms deal.

"We wish to state categorically that the ANC has no relationship with Floryn Investments or with Nkobi Holdings," ANC spokesperson Smuts Ngonyama said.

With acknowledgement to The Star.