The former head of Victoria’s corruption watchdog has accused a Labor-dominated parliamentary committee of seeking to undermine its credibility amid a series of probes into the government.

In December, Independent Broad-based Anti-corruption Commission (IBAC) boss Robert Redlich wrote to the speaker and president over concerns “partisan” politics had intruded into the workings of the Integrity and Oversight Committee (IOC).

He said IBAC first became concerned when Canberra-based auditor Callida tipped the body off it had been directed by an audit sub-committee to “find dirt on IBAC and data that is not readily publicly available”.

“IBAC was advised that the IOC is looking for evidence to support a narrative that ‘IBAC is not performing’,” reads the seven-page letter published in full by the Herald Sun.

Premier Daniel Andrews rejected the allegations his government directed Callida to dig up dirt on the watchdog.

“I reject that completely. That’s simply wrong,” he told reporters on Thursday.

Mr Andrews said he had not seen or read the letter but the make-up of the committee would not change as it had already been confirmed.

“I’m not having a debate with a bloke who used to run an agency,” he said.

Mr Redlich’s five-year term in the role ended last year, with the government appointing an interim commissioner.

Callida was hired in 2021 to conduct an independent performance audit of IBAC and other integrity agencies, as required by law.

The committee published its final report in October but a Labor MP was accused of interference, requesting Callida remove any references to the Andrews government underfunding or under-resourcing IBAC.

The watchdog last year completed multiple inquiries linked to the Victorian Labor government, including a factional branch-stacking scandal.

– AAP