Repatriated Australians in the Northern Territory who've been in interstate hotel quarantine will now have to be re-tested for COVID-19 after they leave the facility.
It comes amid fears the variant of the virus first detected in India could be spread by returned travellers who've completed their mandatory 14-day quarantine period.
The tests will be required three days after they leave hotel quarantine or on day 17 if they come to the NT, Chief Minister Michael Gunner told reporters on Monday.
"This is a direction that reduces the risk to Territorians from interstate hotel quarantine," he said.
"I acknowledge it will be an inconvenience but we've always said we'll do whatever it takes to keep Territorians safe."
People who arrive in the NT after day 17 but before the 28th day since they entered quarantine will still be required to have a test.
"This new direction will give us protection against the exact scenario that we've seen send Melbourne into lockdown again," he said.
"That outbreak started from a returned international traveller who completed their 14 days quarantine in South Australia then returned a negative test."
Acting Chief Medical Officer Charles Pain urged Territorians to get vaccinated to protect themselves and the community.
"This is critical now, we will continue to be faced with the fear that these outbreaks will spread in our community," he said.
"Vaccination is absolutely vital to protect us."
Asked about an incentive program to encourage people to get vaccinated, such as a lottery, Mr Gunner said he wouldn't rule it out.
It comes as the third Qantas plane evacuating Australians from India touched down in Darwin since repatriation flights from the COVID-ravaged country resumed a fortnight ago.
Flight QF112 from New Delhi landed about 9:45am local time carrying 150 people.
Meanwhile, two sisters have allegedly escaped an Alice Springs quarantine facility by abseiling from their room.
The pair, aged 19 and 22, then jumped the perimeter fence into a waiting vehicle, Police Commissioner Jamie Chalker said.
"I can say they were up on the first floor. They managed to abseil down and work through that, and then up and over a fence to head off," he said.
"That's something that's very deeply concerning, again noting this is not a prison."
The women were driven to their mother's home and she later reported them to police.
The women returned to quarantine, accompanied by their mother and one of their boyfriends, a police spokeswoman said.
One of the women was uncooperative when told she'd have to go back to the Todd Facility but eventually complied.
Both the mother and boyfriend have also been directed into mandatory supervised quarantine.
Infringements notices have been issued to both women.
The NT penalty for failing to abide by the CHO's directions is $5056 for an individual and $25,280 for a business.
