A former Newcastle lord mayor has launched a Supreme Court challenge seeking the removal of ICAC Commissioner Megan Latham from an inquiry into a political donations scandal.

The corruption watchdog's Operation Spicer inquiry is investigating claims MPs received and concealed payments from prohibited donors.

Developer and former lord mayor of Newcastle Jeff McCloy gave evidence at the hearings, famously describing himself as a "walking ATM" when it came to handing out money to politicians.

Although the findings are yet to be released, the hearings ended the careers of several Liberal MPs and forced Mr McCloy to resign.

The businessman is already trying to overturn the laws preventing developer donations in the High Court, but he is now taking action in the NSW Supreme Court, seeking to have Commissioner Latham removed.

His legal team will argue her actions before and during the hearings "displayed an apprehension of bias".

Mr McCloy cites a speech Commissioner Latham made to the NSW Bar Association last year, describing the questioning of witnesses during public inquiries as being like "pulling wings off butterflies because you've already worked out what you want to get out of the witness and you know exactly what you expect the witness to say".

Mr McCloy's legal team will also ask the court to stop the ICAC from publishing or presenting to parliament any report relating to Operation Spicer.

The NSW shadow Attorney General Paul Lynch will not say whether he believes the court action is a stalling tactic, but he doubts it will succeed.

"I must say I am quite surprised that there would be a claim of bias or apprehended bias, I'd be very surprised if that claim was upheld," he said.

"It also strikes me as a quite interesting tactic to make this application so long after the event.

"If the things that were alleged in fact happened then you would have thought something would have happened instantaneously rather than such a delay."

The case is due to be heard in Supreme Court on September 16.