Construction workers are too scared to blow the whistle on "rotten" behaviour at government sites, triggering calls to give building watchdogs more teeth.
Victorian Premier Jacinta Allan was handed former justice department chief Greg Wilson's interim report on the state's construction sector this week, with the review publicly released on Friday.
The probe was sparked following allegations of serious criminal activity, including intimidation and coercion within the CFMEU on government worksites.
Ms Allan said the report, which she received on Thursday, would "help us tear a rotten culture out by its roots".
"I want to say to the tens of thousands of construction workers who go to work in this state every single day ... those people deserve a strong union, they deserve the best representation," she told reporters on Friday.
Mr Wilson found there was significant reluctance from workers to make complaints within the construction industry, both because of fear of reprisal and because people lack confidence any action would be taken.
"There is no one body responsible for ensuring there is a culture within Victorian government construction projects that supports the raising and addressing of complaints," he wrote in the report.
Workers who attempted to report wrongdoing struggled to find a body that could address their problem.
"One person described approaching 10 entities over two years, including state and federal bodies and major contractors, and being unable to find anyone who could deal with the issue they were raising," Mr Wilson said.
"There is not a simple 'one-stop shop' for any allegation related to government-funded construction projects."
While agencies such as the Independent Broad-based Anti-corruption Commission and the Auditor-General's Office can investigate corruption in public office, they do not have the powers to look into contracts between private employers on government projects.
Major projects in Victoria are outsourced to several levels of sub-contractors, creating chains of contracts between private companies and individuals, most of which have no direct link to the government.
"Victoria's integrity agencies do not have a role in investigating allegations of corrupt behaviour between private bodies, unions and private individuals of the kind that has led to this review," the report said.
Any reform of corruption regulator powers could create challenging legal questions and stretch resources, Mr Wilson's report found.
Victoria's Infrastructure Delivery Authority has the power to dismiss personnel from government worksites but the review found these have rarely, if ever, been used.
Opposition Leader John Pesutto said the report highlighted the "farce" in the government's response to the CFMEU allegations, which only a royal commission could address.
"Victorians deserve to know the extent to which bikies and organised criminals have infiltrated major projects, how this was allowed to occur, who is responsible and how much it has cost taxpayers," he said.
The Victorian Greens have campaigned for IBAC to be given stronger powers to investigate all forms of corruption.
"We urgently need to bring our watchdogs into line with the rest of the country and give them the teeth to investigate corruption properly," Greens MP Tim Read said.
The CFMEU and all of its state branches were placed into administration by the federal government on August 23, while the Victorian government has announced it will introduce laws to ban organised crime groups from entering government worksites.
The final report will be delivered to the state government by November 28.
