The premier is likely to be grilled on Friday over the fateful decision to hire private security guards to oversee returned travellers, rather than the police or the Australian Defence Force, who assisted in NSW and Queensland.

It comes after Health Minister Jenny Mikakos on Thursday became the third government minister to deny any involvement in the decision to use the guards, following Jobs Minister Martin Pakula and Police Minister Lisa Neville on Wednesday.

READ MORE: Climbers launch legal action against Grampians restrictions

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

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

The premier held a press conference at 3pm, where he told reporters private security would be involved in monitoring compliance with quarantine arrangements.

Staff from the Department of Jobs, Precincts and Regions weren't told to begin looking for security guards until a meeting at the state control centre at 4:30pm.

At that meeting, Victoria Police Assistant Commissioner Mick Grainger said it was Mr Ashton's preference that guards be the "first line of security".

IN OTHER NEWS:

Mr Ashton, meanwhile, told the head of the Australian Federal Police the ADF would be doing transfers to the hotels, where private security would be used as part of a "deal set up by our DPC (Department of Premier and Cabinet)".

Mr Andrews has repeatedly been questioned at his daily press conference as to why the ADF wasn't involved in the state's program.

He told a state parliamentary committee in August that it was "fundamentally incorrect to assert that there was hundreds of ADF staff on offer and somehow someone said no".

"That's not, in my judgement, accurate," he said.

"It's been provided in limited circumstances in NSW, not to provide security as such but to provide transportation from the airport to hotels."

At one of his daily press conferences in August, Mr Andrews said ADF personnel were offered for "compliance monitoring and checking of self-isolation orders".

The inquiry has since heard Victoria rebuffed multiple offers of assistance.

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 premier is the last witness at the $3 million inquiry, headed by retired judge Jennifer Coate.

It will hand down its final report on November 6.

- AAP

Did you know you can receive updates straight to your inbox? To make sure you're up-to-date with news from across the region, sign up below.