New South Wales has recorded a further 20,050 COVID-19 infections overnight, as concerns grow about an Autumn Omicron wave.
The new figures mark a slight drop from the 20,087 cases seen yesterday.
A further six people have died as hospitalisations increased to 1060 but ICU admissions have decreased to 32.
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Victoria has recorded 9036 new cases — also a decrease from yesterday.
As the infectious Omicron BA.2 sub-variant spreads, experts are concerned real case numbers could be much higher.
Health experts will roll out a national COVID-19 surveillance program to get a better picture of what cases could look like.
Researchers will look at around 5,000 anonymous blood samples to see if they can pick up traces of COVID-19 antibodies.
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"Samples for this survey were taken six weeks after the Omicron peak, which is sufficient for antibodies to have developed in people who were infected during that time," says Professor Kristine Macartney, National Centre for Immunisation Research and Surveillance Director.
The data from those samples is predicted to show true number of cases lurking in our community is higher than what's currently being reported.
"We know that relying on reporting of positive tests underestimates the true number of COVID-19 cases, particularly since high vaccine coverage has reduced the proportion of cases with symptoms. Serosurveys help us understand by how much," says Dr Dorothy Machalek, lead investigator on the project from the Kirby Institute.
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Experts expect the first survey results will be released within weeks.
Health experts are urging residents across Australia to remain vigilant and adhere to public health measures.
"(Omicron) is probably just as severe and we have had more deaths this year in 2022 than in the whole of the previous two years," infectious diseases expert Professor Robert Booy told Today on Thursday.
"We have to pay attention. We have to do clever things."
He said a return to lockdown would not be necessary, but people should consider a return to mask-wearing indoors, working from home if possible, and avoiding crowds.
