The commissioner of the state's corruption watchdog has hit back at its inspector, saying he has a clear bias against her.

Commissioner Megan Latham today responded to evidence that the Independent Commission Against Corruption (ICAC) inspector David Levine gave to a parliamentary inquiry on Monday, describing the agency's investigation into Margaret Cunneen's case as a "debacle" which led to "demeaning blood-letting" in the media.

Mr Levine previously wrote a report which slammed the investigation into whether Ms Cunneen told her son's girlfriend to fake chest pains to avoid a breath test.

This led to a high-profile feud between himself and Ms Latham.

The matter is now being investigated by the state parliamentary committee into the ICAC.

Ms Latham told the committee hearing that the commission was denied procedural fairness by the inspector.

"The inspector does not refute it," she said.

"In fact, he reinforced that denial in the course of his evidence, and I quote: 'I had no intention to engage with ICAC in a tit for tat debate about every alleged flaw, legal error, misunderstanding or non-understanding'."

Ms Latham said Mr Levine's evidence on Monday showed he had already made up his mind about whether the Cunneen investigation was worthwhile before he had even looked into it.

"Further, he said: 'Even if the doctrine and principles and practice of procedural fairness were applied at the purest level, the outcome would still be carved in granite'," Ms Latham said.

"The inspector's evidence on Monday discloses 'actual bias' — that is a partial and prejudiced approach to the assessment of the commission's conduct, and my conduct."

Allegations cannot be described as 'legless': Latham

The ICAC commissioner referred to Mr Levine's choice of language on Monday to support her argument that he was biased against her.

"[Words like] 'shenanigans' to describe the commission's procedures, grotesquery, obsession with power ... that my responses included an incomprehensible statement which was made out of desperation and not the exercise of reason," Ms Latham said.

She said the ICAC inspector had gone much further in his attack on her on Monday than he had in the report itself.

Margaret Cunneen has been at the centre of a feud between Margaret Latham and David Levine. ( Fairfax Media: Nic Walker, file photo )

The ICAC commissioner again talked of the important role Ms Cunneen had as a Crown Prosecutor, and why the allegations against her were so serious.

"The allegation being investigated cannot reasonably be described as legless or of fundamental triviality or no more than what an ordinary member of the community as a mother would do in the circumstances," Megan Latham said.

"I invite the members of this committee to consider whether I would be thought fit to occupy the office of commissioner if I advised my son to feign a physical symptom at the scene of a car accident.

"I believed or suspected he had consumed alcohol before driving and I knew that such a symptom would result in his transfer to hospital with the consequent delay of ... a blood alcohol test.

"The answer to that question largely determines the gravity of the allegation that the commission was investigating."

Latham says she has no issue with Levine

Ms Latham admitted she had only met Mr Levine once, despite a memorandum of understanding that said the two should have regular meetings.

She said she had no problem with him, but believed he had an issue with her.

"I don't understand what the problem is," she said.

"I've never had it explained to me why he thinks that I'm sullenly resentful."

The chair of the parliamentary committee, MP Trevor Khan, quipped: "It sounds like a broken-down marriage — both parties say it's the other person's fault."

The commissioner responded by saying she had never attacked Mr Levine the way he had attacked her.

"Mr Khan, all I can say is I have never impuned the inspector's integrity," Ms Latham said.

"I have never called him incomprehensible. I have never said that he had acted out of desperation rather than reason."

The head of ICAC went further, saying Mr Levine had "no professional respect" for her.

She added that she had no vendetta against Ms Cuneen, contrary to what some in the public might think.

"I had had absolutely nothing whatsoever to do with Ms Cuneen professionally," Ms Latham said.

"As a matter of objective fact, I had nothing to do with Ms Cuneen since 1994."

Mr Levine was sitting in the parliamentary inquiry room, occasionally muttering to himself as he listened to Ms Latham's evidence.