Appearing before the hotel quarantine inquiry on Friday, the premier apologised unreservedly to Victorians for mistakes made in the program.

"I want to make it very clear to each and every member of the Victorian community that I am sorry for what has occurred here," Mr Andrews said.

He said he doesn't know who made the decision to use private security guards, rather than the police or the Australian Defence Force, who assisted in NSW and Queensland.

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"I expected that there would be a mix of different personnel playing different roles in the program, including members of Victoria Police," he wrote in his submission to the inquiry.

"But the way in which that decision was to be implemented, including the mix of personnel that would be engaged and their respective roles, was an operational matter."

It comes after Health Minister Jenny Mikakos, Jobs Minister Martin Pakula and Police Minister Lisa Neville denied involvement in the decision to use guards, rather than the police or the ADF.

Victoria Police Chief Commissioner Shane Patton and his predecessor Graham Ashton, Chief Health Officer Brett Sutton, as well as multiple senior public servants, have also pleaded ignorance.

"No one is claiming ownership of the decision, even though no one seems to have spoken against it at the time and no one who might have been the decision-maker seems to suggest if it had been them, it would have been a bad decision," counsel assisting the inquiry Rachel Ellyard said.

Mr Andrews said it was "very disappointing".

The inquiry has heard the decision was made on March 27, the day national cabinet announced the hotel quarantine program.

Following the national cabinet meeting, the premier held a press conference during which he told reporters "police, private security, all of our health team will be able to monitor compliance in a much easier way" at hotels.

He told the inquiry he's not certain why he mentioned private security at that point in time.

"I can't clarify for you or outline for you why I chose those three groups. I'm afraid I have tried to search my recall of this and I simply can't," Mr Andrews said.

"I can't provide you with detail as to why they're mentioned and others aren't."

In his statement, the premier said he had no view on the "appropriateness of using private security as the front line of security" at the time.

In his statement, Mr Andrews states Ms Mikakos and her Department of Health and Humans Services were primarily responsible for the running of the program.

Ms Mikakos told the inquiry there was "shared accountability" between her department and Mr Pakula's Department of Jobs, Precincts and Regions, which contracted hotels and security companies.

"At the start of the program, I regarded Minister Mikakos and Minister Pakula as responsible for informing cabinet about, and seeking cabinet's endorsement of, the initial overall service model and costings that had been determined for the program," Mr Andrews' statement reads.

"I then regarded Minister Mikakos as accountable for the program."

But he regards himself as "ultimately accountable".

Mr Andrews was the final witness before the $3 million inquiry, headed by retired judge Jennifer Coate.

Victoria's second wave of coronavirus, which resulted in more than 18,000 new infections and 750 deaths, can be traced back to outbreaks at two Melbourne hotels used in the quarantine program.

The inquiry will hand down its final report on November 6.

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