IBAC'S TENSE HISTORY WITH THE ANDREWS GOVERNMENT:

LABOR-LINKED IBAC INVESTIGATIONS/REPORTS:

* Operation Naxos - an investigation into allegations Labor MP Khalil Eideh's office misused printing entitlements. Mr Eideh denied the allegations but retired from parliament in 2018

* Operation Watts - a joint investigation with the Ombudsman into branch-stacking within the Victorian Labor party. The report exposed misuse of taxpayer resources by factional powerbroker Adem Somyurek, prompting an apology from Premier Daniel Andrews and a promise of change

* Operation Clara - an investigation into former Labor MP Theo Theophanous's dealings with a developer over a $31 billion proposal to build an education and employment hub in East Werribee. It found Mr Theophanous failed to declare he was lobbying while a member of the Victorian Planning Authority board

* Operation Richmond - an investigation into negotiations between the government and United Firefighters Union on a new pay deal. Its final report is yet to be released

* Operation Daintree - an investigation into the government awarding grants to a Labor-linked union. Its final report is yet to be released

INTEGRITY AND OVERSIGHT COMMITTEE (IOC) INQUIRY:

* Launched into integrity agencies' handling of witnesses following the death of former Casey mayor Amanda Stapledon, who was under investigation as part of IBAC's Operation Sandon probe

* Chair Harriet Shing tells staff in May 2022 to cut the video feed when IBAC commissioner Robert Redlich was asked why Mr Andrews was examined in private for the Operation Watts and Operation Sandon probes

* Mr Redlich expressed "grave concerns" about the inquiry over leaks to the media in a supplementary submission

IOC PERFORMANCE AUDIT OF IBAC AND OTHER INTEGRITY AGENCIES:

* Callida Consulting appointed in 2021

* Audit began in February 2022 and final report tabled in October

* An email from the IOC sub-committee chair, former Labor MP Dustin Halse, directed Callida to delete references in the report to the government underfunding IBAC

KEY QUOTES FROM MR REDLICH'S DECEMBER LETTER:

* "IBAC's experience with the IOC, particularly in the last twelve months, evidences a lack of fairness, partisanship and leaking of information to the media."

* "IBAC first became concerned at a meeting on 14 June 2022, when Callida provided IBAC with alarming advice that they had been directed by the IOC 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'."

* "What is most concerning is that it appears that the chair and majority of the IOC audit sub- committee seemed intent on casting IBAC in a negative light for what we can only assume were political reasons relating to the work undertaken by IBAC."

* "The conclusions of the IOC should not have rested on improperly received information. IBAC had no opportunity to address the information and was provided with no indication of the committee's thinking before a public report was tabled. The process followed was indefensible."

* "There should be a provision that precludes the party in government from constituting a majority of the IOC or the Chair being a member of the party in government."

WHAT PREMIER DANIEL ANDREWS SAID:

* "I reject that completely. That's simply wrong ... I'm not having a debate with a bloke who used to run an agency, who's apparently written a letter that I haven't seen."