The lawyer for Jacob Zuma has described as "misplaced … and misconceived" criticism of Judge Chris Nicholson, who ruled that the decision to bring fresh charges against the ANC president was invalid because he had not been given a chance to make representations.

Lawyer Michael Hulley has filed a 124-page application with the Constitutional Court for the prosecution to be declared invalid on the grounds that the state failed to invite his representations before charging him.

Hulley devotes two pages of the application to conspiracy claims.

Last month, the Supreme Court of Appeal found that the decision to prosecute Zuma was lawful.

It handed the ANC leader a punishing costs order for repeatedly making his "cut and paste" claims against Thabo Mbeki, while he was president, and the state that they were involved in a political plot against him.

In his judgment, Nicholson had said there were grounds to infer there had been "political meddling".

The appeal court criticised this finding, saying it was based largely on "unconfirmed newspaper speculation".

In the papers filed with the Constitutional Court, Hulley seeks to prove that Nicholson's inferences about interference arose through the actions or omissions of the NPA.

He says the NPA asked Nicholson to strike the political conspiracy claims out of Zuma's application for his prosecution to be declared invalid. But the NPA did nothing to show they should be struck out, he says.

"The onus to establish vexatiousness or the scurrilous nature was on the National Director of Public Prosecutions," Hulley argues.

"Left with little or no guidance in the form of argument and debate, (Nicholson) was required by the NPA to make a decision left largely to his own devices."

According to Hulley, the high court judge was unable to find, from the material placed before him by the state, that Zuma's claims were vexatious or scurrilous.

He said that it was "difficult to understand" the NPA's complaint - which was supported by the appeal court - that Nicholson did not properly debate Zuma's claims and the state's response to them before making his inference of political meddling.

"Much of the criticism of (Nicholson's) findings is, with great respect, misplaced."

The NPA has 10 days to file papers opposing Zuma's application.

Meanwhile, Zuma's appearance before Judge Leona Theron in the Pietermaritzburg High Court today is expected to be brief and a mere formality.

Sources said the courtroom had been set aside for 45 minutes but the hearing would probably not take that long.

Zuma's appearance follows the appeal ruling that in effect reinstated the charges against him of corruption, fraud, money laundering and tax evasion.