Australia has had its biggest daily increase in coronavirus cases with 502 people diagnosed with the disease as Victoria's count continues to rise dramatically.
Victoria accounted for 484 of the new cases reported on Wednesday as authorities plead with people to heed warnings to stay at home if they have any flu-like symptoms and while waiting for test results.
The previous highest number of new infections in a day was 469, reported on March 28.
Unlike then, nearly all of Wednesday's new infections were contracted locally.
Deputy Chief Medical Officer Michael Kidd said 98.8 per cent of the more than 2400 new cases detected over the past week were locally acquired, not in people who had picked it up overseas.
"We reported only two cases on June 9, less than six weeks ago, and this shows how quickly outbreaks can occur and spread," he told reporters in Canberra.
"If you have symptoms, you must stay at home. You must not go to work. You must not go to school, you must not go shopping.
"Clearly the figures released today are very significant and they provide a stark reminder that we must all be playing our part in stopping the spread of COVID-19."
After a month with no coronavirus deaths to mid June, Australia has suffered 25 fatalities in the past four weeks as the toll rose to 128 on Wednesday.
And the country is quickly heading back toward the peak of 4935 active cases reached on April 4 after dropping below 400 last month.
Almost 90 per cent of the 3810 people to contract the disease in Victoria in the past two weeks did not self-isolate in the period between feeling sick and getting tested.
More than half didn't isolate while waiting for their results.
Victorian Premier Daniel Andrews warned the current six-week lockdown due to end next month would be extended if the infection rate did not fall.
"You must go and get tested when you feel sick. That is the only thing that you can and must do," he said in Melbourne.
Face masks will be mandatory in greater Melbourne and the Mitchell Shire to the city's north from Thursday.
The federal government predicts Victoria's increased restrictions will cut $3.3 billion from national economic growth in the September quarter.
Australian Medical Association president Tony Bartone is urging national cabinet, which meets on Friday, to take a consistent approach to masks in preparation for other outbreaks.
"Every Australian in current areas of community transmission must make mask use part of their daily routines," he said.
NSW Premier Gladys Berejiklian has stopped short of making face coverings mandatory.
But she's urging people to avoid non-essential travel and exercise extreme caution after the state recorded 16 new cases on Wednesday.
Queensland and South Australia recorded one new case each.
Prime Minister Scott Morrison backed the Victorian and NSW governments' approach on masks.
He wore a mask during a medical appointment recently and has no qualms about being seen with a face covering in public.
© AAP 2020