Deputy President Jacob Zuma avoided embarrassing questions in parliament on Wednesday as ruling party officials quashed opposition attempts to grill him over his financial adviser's bribery trial.

Zuma, seen widely as a possible successor to President Thabo Mbeki in 2009, denied the scandal had created a "black spot" on his reputation.

"Not at all, I don't look at it that way," he said in reply to a question in parliament, before further questions on the matter were prohibited.

Zuma's financial adviser Schabir Shaik went on trial last month accused of paying him bribes, apparently in exchange for his influence when vying for arms and other major government contracts. Shaik has denied the charges while Zuma himself has not been charged in the case.

Investigators claim Shaik paid about R1,3-million between 1995 and 2000 to Zuma, who frequently faced financial problems.

Speaker of Parliament Baleka Mbete of the ruling African National Congress ruled against further questions relating to the court case, prompting heated exchanges with the members of the opposition Democratic Alliance, some of whom shouted "cover up" as she made her decision.

She told legislators the issue should not be addressed in parliament as the court case was ongoing.

"Today provides the perfect opportunity for the deputy president to tell the public the facts without in any way affecting the outcome of the Shaik trial," DA chief whip Douglas Gibson had argued.

The country's former chief prosecutor had said there was "prima facie" case against Zuma in relation to the Shaik case, but declined to prosecute because it was unwinnable in court.

Zuma, a widely popular figure in the ANC and seen as the frontrunner to replace Mbeki when his term ends in 2009, has said he is being subjected to "trial by media" orchestrated by his political enemies.

Shaik has pleaded not guilty to the charges, and says he made the payments to Zuma, a close friend, to help him out of financial problems.

With acknowledgements to Gordon Bell and Reuters.