Victoria's former integrity watchdog commissioner Robert Redlich says the state government's defeat of two bills that would have strengthened the Independent Broad-based Anti-Corruption Commission (IBAC) is a missed opportunity.

The bills from the Greens and Coalition to give more powers to IBAC were voted down in parliament last week.

"We are not in the habit of voting for things that won't work," Premier Daniel Andrews said on Wednesday.

Mr Redlich said he was disappointed IBAC reforms were not passed in parliament last week.

"It is a missed opportunity," he told 7.30.

"The government should give serious consideration for the reasons why the federal parliament has provided the National Anti-Corruption Commission with a much broader jurisdiction."

The reforms followed up on Mr Redlich's recommendations for reforming IBAC and included removing the requirement for IBAC to only investigate if conduct is potentially criminal.

The change would allow probes into grey-level corruption that may not be illegal but still represent serious misconduct.

It is the same threshold for an investigation that applies to the National Anti-Corruption Commission (NACC) and the New South Wales Independent Anti-Corruption Commission (ICAC).

"That enables conduct that's not criminal, but which is improper, where decisions are made for inappropriate reason, to be part of the integrity commission's jurisdiction," Mr Redlich said.

"The jurisdiction of the [IBAC] commission can only be enlivened, where the view has been formed, that there's a reasonable suspicion that it's giving rise to a criminal offence.

"It's important to understand, that integrity in government is about when decisions might be made for the wrong reasons for improper reasons," he said.

Mr Redlich added: "Many decisions which are made for improper purposes are not criminal.

"If a person in government decides to exercise their power to make a decision because they've been bribed ... everyone readily understands that's a crime."

However, Mr Redlich said that if the same person were to make that same decision for a political purpose instead, that was also wrong and should be investigated.

He said when the legislation prescribes that an agency can only look at conduct if it is a criminal matter, then a great deal of misconduct is not captured by an integrity agency.

Former commissioner urges reforms

In an exclusive in-depth interview with 7.30, Mr Redlich explained why the reforms he proposed to strengthen the agency are vital to upholding integrity in the state.

The former Supreme Court judge headed up IBAC from 2017 to 2022. The Victorian government is yet to appoint a permanent replacement.

Mr Redlich's investigations brought the dark underbelly of decision-makers and those in power out of the shadows.

He's now sounding the alarm about the state of integrity.

"I feel that I would be failing the community if I didn't utilise the knowledge I had to draw attention to these matters," Mr Redlich said.

Mr Redlich has also expressed his disappointment about how he was treated at the Integrity and Oversight Committee hearing where he was not able to detail his reforms that would strengthen the body.

"I was given six matters that the committee was willing to explore in relation to recommendations for improving the commission's capacity to investigate; those four members were not interested in exploring any of those matters," Mr Redlich said.

Instead, Labor committee members Belinda Wilson, former actor-turned-MP Paul Mercurio, Ryan Batchelor and Jackson Taylor asked Mr Redlich a series of unrelated questions that occupied most of the committee hearings' time.

"I regret to say that it was an example of members of the committee pursuing political considerations, rather than being focused on what might be done to improve integrity in this state," he said.

It was the latest episode in what appears to be an attack on the integrity watchdog.

In March, a letter by Mr Redlich written in the final weeks of his term last year was tabled in parliament.

It outlined his concerns about the Labor government's attack on IBAC and included allegations MPs had instructed an independent consultant to dig up dirt on IBAC as evidence to support the narrative it was not performing.

Mr Andrews dismissed Mr Redlich's concerns at the time, saying: "I am not here to have debates with people who no longer hold a position and have apparently written a letter I haven't even seen."

Robodebt public hearings likely not possible in Victoria

In 2019, the Andrews government was criticised for raising the bar for public hearings.

Mr Redlich told 7.30 the move has weakened the integrity body, and has called for the threshold for public hearings in Victoria to be lowered.

He says under the current rules, inquiries like Robodebt would most likely be held behind closed doors.

"If that were a matter that arose in Victoria, I think it's highly unlikely that we would have been able to hold public hearings because that conduct, whilst as I say, was equally damaging to the public interest, was not criminal conduct."

Mr Redlich said public hearings are an important mechanism to help the public understand what the work of the commission is doing and therefore "understand where there are failings in the way in which executive government operate".

He also says it's highly likely the public grilling of former NSW premier Gladys Berejiklian would not have happened under IBAC.