Victoria's hotel quarantine inquiry has been unable to identify a single person responsible for the fatal decision to use private security guards in the program.
The state's second wave of coronavirus, which resulted in more than 18,000 new infections and 800 deaths, can be traced back to security guards working at the Rydges on Swanston and Stamford Plaza hotels in May and June.
In the $5.7 million inquiry's final report, released on Monday, retired judge Jennifer Coate describes the decision to use security guards as an "orphan", with "no person or department claiming responsibility".
"Ultimately, the evidence did not identify that any one person decided to engage private security in the program," she concludes.
However, Ms Coate singles out then-police chief commissioner Graham Ashton, who was consulted and "expressed a preference that private security perform that role and Victoria Police provide the 'back up'".
Mr Ashton's "clearly persuasive" position was relayed during a state control centre meeting on the afternoon of March 27, the day before the hotel quarantine program began.
"There being no particular discussion or dissent, this set in motion the actions, that evening, by (the Department of Jobs, Precincts and Regions) to commence contractual engagement with three security firms," the report reads.
Ms Coate said no one at the meeting gave any consideration to using Australian Defence Force Personnel for enforcement.
She concluded ADF personnel were most likely available to assist at the hotels from April 8, though she was not able to say whether their presence would have removed the need for private security guards.
Ms Coate effectively cleared Premier Daniel Andrews, former health minister Jenny Mikakos and senior ministers Martin Pakula and Lisa Neville, finding the decision to hire guards was not made at a ministerial level.
"Neither (the premier) nor his ministers had any active role in, or oversight of, the decision about how that enforcement would be achieved," the report reads.
Ms Coate said not one of the 70,000 documents handed to the inquiry "demonstrated a contemporaneous rationale for the decision to use private security as the first tier of enforcement, or an approval of that rationale in the upper levels of government".
"Such a finding is likely to shock the public," the report reads.
She said the role performed by security guards in the program was "ill-defined from the beginning and was, ultimately, a role not suited ... to the cohort of guards that was engaged".
"Consideration was not given to the appropriateness or implications of using a largely casualised workforce in an environment where staff had a high likelihood of being exposed to the highly infectious COVID-19," Ms Coate said in the report.
"This, of course, had flow on impacts in terms of the spread of the virus."
The report, however, did not blame the guards, finding they acted "honestly and with goodwill".
"None of those workers went to work to get infected with COVID-19. However, systemic governmental failings led to problems."
The report found both federal and state governments lacked an up-to-date pandemic plan, including for mandatory mass quarantine.
It left public servants scrambling to set up the "unprecedented and complex" program within 36 hours.
Responsibility for cleaning, training and the supply of personal protective equipment was largely outsourced, while the Department of Health and Human Services failed to accept its role as the lead department responsible for running the program.
Ms Mikakos, DHHS secretary Kym Peake and Department and Premier and Cabinet secretary Chris Eccles have already resigned over the scandal, while a reset program started earlier this month.
The premier apologised to Victorians for the program's failures, singling out those who had lost a loved one as a result of the second wave.
"There will be people missing from the Christmas dinner table on Friday and I am deeply sorry and saddened by that," Mr Andrews told reporters on Monday.
"We have learnt those lessons. We have made those changes. We will carefully consider all the recommendations that Judge Jennifer Coate has made."
The final report makes 12 recommendations on top of 69 made in the inquiry's interim report, including updating Victoria's pandemic plan and further exploring mandatory testing for returned travellers.