Hotel operators, private security companies and state government decision-makers will be hauled before Victoria's inquiry into the botched coronavirus quarantine program.
The state government launched the investigation, headed by retired judge Jennifer Coate, after new COVID-19 cases in late May and early June were linked to infection control breaches by security guards at quarantine hotels.
"Information already available to the inquiry suggests the possibility of a link between many of the cases of coronavirus identified in the Victorian community in the past few weeks and persons who were quarantined under the hotel quarantine program," senior assisting counsel Tony Neal QC said.
"Comments made by the chief health officer to the media have suggested that it may even be that every case of COVID-19 in Victoria in recent weeks could be sourced to the hotel quarantine program."
The decisions and communications between the government, hotel operators and private contractors will be examined and submissions have been ordered from them by the end of July.
That includes the Department of Health and Human Services, Department of Jobs, Precincts and Regions, Department of Treasury and Finance, Department of Premier and Cabinet, Victoria Police, Emergency Management Victoria and Ambulance Victoria.
Two hotels with known large coronavirus outbreaks, Rydges on Swanston and Stamford Plaza have been put on notice, along with Travelodge Melbourne, Park Royal Hotel Melbourne Airport, Holiday Inn Melbourne and Four Points Sheraton.
The eight security companies of interest to the inquiry are Wilson Security, United Risk Management, Unified Security Group, Ultimate Protection Services, MSS security, Elite Protection Services, Australian Protection Group and Security Hub.
Medical experts, hotel staff and returned travellers who stayed in quarantine will be called to give evidence.
Employers face significant penalties if they attempt to deter employees from giving evidence to the inquiry.
"I expect no less than full, frank and timely cooperation from all government entities and persons to enable me to do my job for the people of Victoria," Justice Coate said.
It is not known if Premier Daniel Andrews, Health Minister Jenny Mikakos or Chief Health Officer Brett Sutton will be called to give evidence, but Mr Andrews said neither he nor any government minister had been approached.
"I won't tell a former judge how to do her work. She will call whomever she thinks she needs to call. Anyone who is called should turn up," Mr Andrews told reporters on Monday.
"What has gone on here is completely unacceptable to me - and unacceptable to all of us."
Opposition Leader Michael O'Brien said Mr Andrews and responsible ministers should front the inquiry.
"When the government has made mistakes and people have died as a result, Victorians need answers. First of all to work out what went wrong and secondly to make sure nothing like this can ever happen again," he said.
Corrections Victoria now manages the hotel quarantine program.
International flights have been diverted from the state until the situation is under control.
Public hearings will be held from August 6 and a final report is due on September 25.