Victorian Premier Daniel Andrews has warned that Melbourne's lockdown could extend beyond six weeks if things are not brought under control.

He made the warning on The Project and said that a longer time frame "can not be ruled out".

Around 5.2 million people who live in the Melbourne metropolitan area have returned to stage three restrictions from 11:59 pm on Wednesday/ as the state has announced over 100 new cases for four days straight.

“It’s not about being popular, it’s about doing what has to be done”. Daniel Andrews spoke to us, as Victoria records 134 new COVID-19 cases today, as people in Melbourne and the Mitchell Shire savoured their final hours of freedom for six weeks.#TheProjectTV pic.twitter.com/CVdyy0MjZd

— The Project (@theprojecttv) July 8, 2020

"The advice from our chief health officer, that six weeks will give us the time we need to get control of this virus again, to see some stability and then to drive down the case numbers," he said. 

"We can’t rule out that it may be longer, but that’s the advice of the Chief Health Officer, after a lot of thought, a lot of analysing of that data, we couldn’t go on as we were. 

"We needed to take this painful and difficult step and six weeks is the time we need."

Victoria currently has 860 active cases of coronavirus with 465 are community transmissions.

The Project's Waleed Aly asked the Victorian Premier on Wednesday night if it was a mistake that the army wasn't enlisted to enforce hotel quarantine.

"Do you accept that it was a mistake not having ADF personnel running or overseeing the hotel quarantine program?" Waleed questioned. 

"Well, there are a couple of points to make, Waleed," Mr Andrews responded.

"ADF personnel are involved in transportation in some states and other states they have no role at all.

"We have other problems and we've set up a judicial inquiry because you've got to being accountable, yes, but I would put it to you with the greatest respect, it is not appropriate for politicians to sit in judgement of themselves.

"It should be at arm's length, should be done properly."

The premier said that Corrections Victoria was now "absolutely in control" of the quarantine facilities.

"They are the people who run our jails, the people who are perfectly skilled and suited to do this," he said.

"We've also got a freeze on additional flights coming back to Melbourne. That will only resume if we are completely confident, if the corrections commissioner is completely confident that we have all the processes in place."

Aly asked that if the premier's apology to Melbourne citizens earlier in the day was "admitting fault".

"The job that I do means that I am the leader of the state, and it is for me to accept responsibility for all of these things … I’ve never run away from that," Mr Andrews responded.

"These are not easy calls, but it is not about being popular. It is about doing what has to be done. I am deeply sorry that we find ourselves here, but words are not the most important thing.

"It is acknowledging, of course, being accountable, of course, but then taking the tough calls and getting on to get this job done and that’s what I intend to do."

His interview comes after Prime Minister Scott Morrison told Melbourne citizens that they would have to "tough it out".

"The job if you’re a Melburnian is to tough it out – and it will be tough – but know the rest of the country is with you," he said.

"The rest of the country knows that the sacrifice that you’re going through right now is not just for you and your own family, but it’s for the broader Australian community."

The Prime Minister also said he was grateful for their strength.

"I want to thank Melburnians for how they’re dealing with this. I can imagine the frustration," Mr Morrison said.

"You can imagine a business that had just started opening up again and now they got to close down again. Heartbreaking. Frustrating. Talking to their staff, kids were about to go back to school, the uncertainty that is attached to all of that – we all understand."