The Labor government has faced months of mounting pressure to call a royal commission after allegations by corruption-busting lawyer Geoffrey Watson SC that taxpayers lost an estimated $15 billion due to dodgy deals related to Big Build public projects.
In his first act as premier, Ben Carroll on Tuesday backflipped on his predecessor Jacinta Allan's refusal to call a royal commission into the embattled construction industry and its rogue union, the CFMEU.
Opposition Leader Jess Wilson sent a formal letter to Mr Carroll on Saturday afternoon demanding the inquiry "extend beyond the conduct of the union", calling for senior officials, ministers and former premiers to give evidence at public hearings.
The email attached the opposition's draft terms of reference for the inquiry.
Labor is yet to outline its proposed scope.
"As you rightly identified ... those terms of reference must be expansive," Ms Wilson wrote.
"They must also specifically examine - at public hearings as a matter of urgency - the knowledge and culpability of what current and former premiers, ministers and senior officials knew."
The opposition's terms broadly demand an investigation into the influence of the construction union, the procurement process for contracted jobs, whether decisions were influenced by donations or anticipated political advantage, government knowledge and disclosure and the flow of public money.
The papers also included a 25-name list of desired inquiry witnesses, including current and former premiers Ben Carroll, Daniel Andrews and Jacinta Allan, senior government ministers and public servants, industry heavyweights such as former CFMEU boss John Setka and underworld figure Mick Gatto.
Ms Wilson requested the Carroll government consult with the opposition on the final terms of reference, the appointment of the commissioner to oversee the inquiry and its "timing, powers and resourcing".
"We will not support narrow terms designed by Labor alone or the appointment of a commissioner without meaningful consultation," she told reporters on Sunday.
"Victorians deserve a genuine inquiry, not one structured to limit scrutiny of the government responsible for the Big Build."
Unveiling a hospital care centre in Melbourne's northern suburbs, Mr Carroll said he was yet to read Ms Wilson's message but pledged to ensure the inquiry's terms of reference would be "wide and exhaustive".
He said he was working with Victoria Police Chief Commissioner Mike Bush to get "on with the job of the terms of reference".
Mr Carroll did not directly answer questions about whether former premiers and other Labor Party members would be called as witnesses.
"What I can promise is I will take my advice from the chief commissioner," he said.
"Everyone should be questioned that the royal commissioner believes had a role."
Mr Carroll said he intended to start the royal commission before late November's election and he would be happy to appear as a witness.
Federal shadow treasurer Tim Wilson has also called for Prime Minister Anthony Albanese to launch a national inquiry into CFMEU conduct on government worksites.
But other coalition figures have not backed up the suggestion, including deputy Liberal leader Jane Hume, who instead questioned the prime minister's response to alleged corruption in building projects.
"It is passing strange that Anthony Albanese has shown such extraordinary lack of curiosity and lack of interest in the extent of corruption on construction sites right around the country, particularly when there is federal commonwealth taxpayer money that has been involved," she told the ABC's Insiders program.
The Albanese government forced the CFMEU's construction and general divisions into administration nationwide in August 2024 after allegations crime figures and other rogue elements had infiltrated the union.
