State leaders are looking at tougher restrictions to slow the spread of coronavirus as Australia's death toll rises to 13.
However, top health officials say it could be a week until the effect of a second wave of shutdowns, which began on Thursday, reduces case numbers.
Prime Minister Scott Morrison joined US President Donald Trump and other members of the G20 through a video link-up overnight.
The leaders have struck a deal to co-ordinate efforts to tackle the coronavirus pandemic, collectively pledging $A7.5 trillion to kickstart the global economy.
The number of confirmed cases in Australia has risen to about 3000.
Health officials are begging Australians to stay at home if they are sick and to keep their distance from other people even if they're healthy.
Labor has urged the government to put tougher measures in place, with deputy leader Richard Marles saying current steps weren't enough to stop exponential growth in cases.
"That is a recipe for being behind the game," he told the Nine Network on Friday.
The Greens are pushing for a full lockdown.
But the government says it doesn't want to rush into tighter measures, given strict restrictions were put in place just days ago.
Senior health official Michael Kidd has reminded Australians to be "absolutely scrupulous" with washing their hands, to keep 1.5 metres away from others and to stay at home when sick.
"Everybody has to do their part in making sure that we are protecting each other, and especially protecting the most vulnerable people in our society," Professor Kidd told ABC News.
Australia has tested more than 178,000 people and deputy chief medical officer Paul Kelly says the rate of positive tests is low, at about 1.5 per cent.
Three Victorian men and one from Western Australia, all aged in their 70s, were confirmed on Thursday as Australia's latest fatalities.
Queensland, South Australia and Western Australia joined Victoria and the ACT in moving school holidays forward to give teachers time to switch to online learning.
Teachers will still be at schools so parents who have essential jobs, such as healthcare workers and supermarket shelf-stackers, can send their children.
But all other students are being asked to stay home.
Professor Kelly says millions of masks are expected to arrive in Australia over the coming months.
The nation has already had two waves of business closures this week - leading to thousands losing their jobs - in a bid to stop people gathering in large numbers or in closed spaces.
Thousands more businesses were shuttered on Thursday and many large retailers stood down staff and closed stores voluntarily.
NSW and Victorian leaders are foreshadowing further moves, potentially including full statewide lockdowns, if the increase in new cases doesn't slow.
© AAP 2020