Federal Health Minister Greg Hunt is confident Victoria will succeed in beating the coronavirus, while backing Premier Daniel Andrews' decision to make the wearing of face coverings compulsory.
The mandatory wearing of masks will begin on Wednesday in the lockdown areas of Melbourne and Mitchell Shire, with those failing to wear one coping a $200 fine.
It comes as a further three coronavirus-linked deaths were recorded on Sunday, taking the national toll to 122.
The number of infections in Victoria also jumped again to 363, after dipping to 217 on Saturday.
Mr Hunt, a Victorian himself, said the wearing of masks was necessary because of the level of community transmission in the Melbourne region and surrounding areas.
"We are sorry that it has reached this point for all those who were affected. But this is about saving lives and protecting lives," Mr Hunt told reporters near Melbourne on Sunday.
He said in Australia there were six states and territories which had effectively zero community transmission. In the seventh, NSW is conducting a "herculean tracing task".
"In Victoria, that task is with us," he said.
"Do we believe that Victoria can succeed and that we can beat this virus? Yes, we do. And yes, I do. So I want to give that sense that, amidst the darkness, there are lights of hope. Clear and real and visible."
He also announced the federal government would be providing a further 272 ADF personnel to the state to help with border control and contact tracing, as well as providing one million masks for workers in aged care and disability centres and the provision of five mobile testing teams.
Mr Andrews said as there was no vaccine to this "wildly infectious virus", habits had to change.
"Most of us wouldn't leave home without our keys, we wouldn't leave our home without our mobile phone. You won't be able to leave home without your mask, and then wear it where it is absolutely essential to stop the spread of this virus," he told reporters in Melbourne.
Victorian authorities are also kicking off a major inspection and enforcement blitz on at-risk workplaces in an attempt to stem the spread of the virus.
"There is no room to cut corners or be complacent," Workplace Safety Minister Jill Hennessy said in a statement.
Meanwhile, NSW is now limiting international arrivals into Sydney to 350 passengers a day from midnight.
Premier Gladys Berejiklian said the step was necessary to make sure the state stayed in a strong position to prevent the spread of coronavirus.
"NSW is the gateway to Australia and it is important that passengers returning home do not overrun the capacity of NSW Health and hotel quarantine."
It further reduces the current cap of 450 people introduced on July 5.
The state reported reported 18 new COVID-19 cases, with the total number of cases associated with the Crossroads Hotel cluster in southwestern Sydney now 45.
Queensland has just two active coronavirus cases after another day of zero positive tests.
Premier Annastacia Palaszczuk wants the NSW 'border' moved south to ease congestion at checkpoints where local streets have become choked with traffic as motorists face long delays.
Queensland is now a safe haven for Melbourne's AFL clubs and the Super Netball season.
All Super Netball teams will relocate to Queensland with games to be played in Cairns, Townsville, Brisbane and the Gold Coast.