The Northern Territory has recorded one new case of COVID-19.
The man was a close contact of the first case linked to the Tanami mine, Chief Minister Michael Gunner said.
No decision will be made on the lifting of the lockdown today.
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That decision will be made based on tomorrow's case numbers.
When the lockdown is lifted, it is likely some restrictions will remain including mask-wearing, NT Chief Health Officer Dr Hugh Heggie suggested today.
The new case arrived in Darwin on Friday and was transferred to Howard Springs.
His first COVID-19 test returned a negative result but he has since tested positive overnight.
Mr Gunner said there was no reason to believe he had been in the community while infectious.
Alice Springs is now almost 24 hours into its 72-hour lockdown after the Alice Springs Airport was yesterday identified as an exposure venue.
Although the man is unlikely to have been infectious while at the airport, Mr Gunner said he wasn't prepared to "take any punts".
"The population is too vulnerable. The stakes are too high," he said.
Authorities have identified 69 close contacts and 52 casual contacts who spent time in the airport cafe on Friday.
One woman who broke a self-isolation order in Jabiru in Kakadu National Park has also been sent to the Howard Springs facility.
There have been no positive tests linked to the woman.
Mr Gunner said he was "disappointed rather than concerned".
There were 3500 COVID-19 tests conducted yesterday in the Northern Territory.
Mr Gunner urged patience with long lines at testing clinics and encouraged people to only get tested if they were a close or casual contact or if they developed symptoms.
Dr Heggie said symptoms may be unusual, including a subtle loss of taste, or diarrhoea.
Cracker Night postponed
Mr Gunner confirmed all Territory Day celebrations had been postponed.
The day, observed on July 1, is usually celebrated with fireworks, concerts and events, and is otherwise known as "Cracker Night".
It celebrates the Territory achieving independence from the Commonwealth in 1978.
