Zero cases were reported in the 24 hours between 20:00 on Friday and 20:00 on Saturday - the first time this has happened since 9 June.
The state of Victoria - epicentre of Australia's second wave - recorded zero cases for the second day in a row after a 112-day lockdown.
Health officials say more restrictions may be eased in the coming days.
"Thank you to all of our amazing health & public health workers & above all else the Australian people," Health Minister Greg Hunt said on his Twitter account.
Australia has recorded some 27,500 infections and 900 deaths to Covid-19 since the pandemic started - far fewer than many nations.
The nation of 25 million adopted an approach of using lockdowns and proactive testing and tracing to contain the virus, and Victoria - where 90% of Covid deaths occurred - imposed some of the severest stay-at-home and curfew rules in the world.
Victoria and its largest city Melbourne began to reopen earlier this week after recording no new community-transmitted cases since June. People were able to freely leave their homes, retail stores, restaurants, cafes and bars could reopen and groups of up to 10 could start gathering.
Victorian Premier Daniel Andrews praised the state's six million residents for following such strict rules and said they were well placed for a "Covid-normal Christmas".