The leader of the official opposition has weighed into the Schabir Shaik trial by suggesting that Deputy President Jacob Zuma could have cleared his name already.

Democratic Alliance leader Tony Leon also said Zuma should be charged if any new evidence emerges in the trial.

Addressing the Northern Cape DA congress on Sunday, Leon said the justice system was on trial in Durban along with Shaik.

"If the cabinet is upset that the media is speculating about allegations against Zuma, that is too bad," Leon said.

"The deputy president and the government have only themselves to blame. If Zuma is innocent then he should immediately have sued the National Prosecuting Authority and the relevant media," Leon said.

Leon said this is what he did when a New National Party politician once accused him of potential criminal activity – "and the matter was put to rest very quickly".

Although Zuma is not on trial, his name appears on every page in the charge sheet against Shaik.

"There were also other steps that could have been taken. President Thabo Mbeki was requested to widen the terms of reference of the Hefer Commission to include allegations of corruption involving Zuma. He did not," Leon continued.

"The deputy president himself could have given evidence to that commission in order to clear his name. He did not."

Zuma did, however, successfully lay a complaint with the public protector against former NPA head Bulelani Ngcuka and former justice minister Penuell Maduna for saying there was a prima facie case of corruption against him, but not enough evidence to prosecute him.

Leon argued that it was seldom that one party in an alleged bribery case was charged and the other not. "We are left to conclude that political pressure may have been applied.

"It is therefore no use for the cabinet to complain that the deputy president is being tried by the media when the government itself made sure he would not have any other kind of trial.

"The cabinet should worry more about applying its code of conduct to its members.

Sparks are expected to fly today when a former employee of Shaik's gives evidence.

With acknowledgements to Christelle Terreblanche and The Star.