Australians are being urged to remain vigilant about coronavirus despite falling infection rates across the country.
Victoria recorded just 11 new cases on Monday, along with two deaths.
"This is not just a good day, this is a great day," Premier Daniel Andrews told reporters in Melbourne.
"We are seeing these numbers come down, the strategy is working."
However, Victoria's 11 new cases were detected from just 7164 tests.
Deputy Chief Medical Officer Nick Coatsworth said he was concerned about the decline in testing rates nationally, but did not think it was masking large numbers of undetected cases in the community.
The latest national testing figures show a 30 per cent fall in the past three weeks.
"The percentage positivity has stayed the same," he said.
However, he urged more people to get tested, especially as the overall strategy was to detect people with COVID-19, find clusters of cases and then sort out the clusters before they became outbreaks.
"We can only ask Australians with even the most minimal of symptoms - even if you think you have hayfever - if you haven't had a COVID-19 check you need to go and get tested," Dr Coatsworth said.
He acknowledged lifting testing rates would become harder "because we are moving into the months of the year where there is less respiratory virus".
NSW has recorded four new cases of coronavirus including three returned overseas travellers in hotel quarantine and one person linked to a known cluster.
The results were drawn from 7765 tests, which was almost half the number conducted the day before.
NSW Health said while it was not unusual for testing numbers to drop over the weekend, it would like to see levels above 20,000, particularly in southwest Sydney.
There are hopes Victoria's declining case numbers could bring about an early end to lockdowns in Melbourne.
Dr Coatsworth said there was still some way to go.
"When Victorians come out of restrictions, particularly in Melbourne, the complacency has to be avoided," he said.
"We know how to stop this virus, if we limit household gatherings, wash hands frequently and have the COVIDSafe app downloaded and maintain physical distance.
"And of course mask-wearing being mandatory, these things will allow us to lift restrictions safely."
Just as Victoria's falling coronavirus cases provide some cause for optimism, NSW is conducting a major contact tracing exercise after a taxi driver tested positive.
The driver worked across Sydney for more than a week while potentially contagious.
Anyone who took taxis across the city's west and southwest between September 8 and 18 is being urged to monitor for symptoms.
"Fortunately that taxi driver had COVIDSafe installed on their phone, which will be assisting contact tracers at the moment," Dr Coatsworth said.
"They did exactly the right thing by getting themselves tested and now the public health authorities will be working overtime to make sure that those particular cases do not turn into a larger outbreak."
The taxi case is concerning health officials in South Australia as they weigh up lifting the 14-day quarantine requirement for people coming from NSW.
Just one new coronavirus case was recorded in Queensland on Monday, a teenage girl in hotel quarantine after returning from overseas.
Australian Associated Press