Australia's capital has recorded two new COVID-19 cases, with Canberra's outbreak growing to six.
One of Friday's infections is linked to a local man who was infectious in the community between Sunday and Wednesday.
A 14-year-old student from Gold Creek School is also infected and it's unclear how they got the virus.
Cases are expected to increase, but health authorities hope a lockdown until next Thursday will let them contain community spread.
More than 3,900 people have been identified as either close or casual contacts and ACT Chief Minister Andrew Barr expects that number to grow.
The ACT's first case in 13 months was confirmed on Thursday as a man in his 20s from the northern suburb of Gungahlin.
Three of his close contacts were also revealed to have the virus.
Concerns about NSW's virus leakage will be raised by chief ministers and premiers during national cabinet on Friday.
Mr Barr earlier pointed to "mixed messages" coming out of NSW about when and how quickly it would move to relax restrictions.
People cue in long lines outside a walk-in COVID19 testing clinic in Weston Creek, Canberra, Thursday, 12 August, 2021. Source: AAP
"What's been expressed inside the national cabinet room is not that they would get to 50 per cent vaccination and then just do a free-for-all, but that they may be able to adjust some of the perimeters of their lockdown," he told ABC radio.
"It would be insane for them to just open up and have no public health directions but that is not my understanding of their position."
NSW and the ACT have effectively shut their borders to each other.
But there are limited exemptions for border communities who need to go in and out of Canberra for essential work or to access healthcare.
"Looking at what NSW put out late last night, it seems that you have to declare that you had been in the ACT but you would be allowed to travel for essential reasons," Mr Barr said.
He conceded it was confusing for residents living in towns bordering the territory and wanted NSW to provide more clarity.
"What I'm hearing is that ACT people have a very clear understanding of our rules and that NSW residents coming into the ACT have a very clear understanding of the ACT position, but that NSW could benefit from clarifying things a little," he said.
NSW Premier Gladys Berejiklian said the situation for communities near the ACT was evolving.
"People are concerned about various movements that have occurred overnight from the ACT to parts of our south coast," she told reporters as NSW recorded 390 new locally acquired cases.
"If we need to do anything as a pre-emptive move, we will."
Federal support is being extended to ACT businesses and residents who have lost work.
Meanwhile, a 20-year-old Canberra man has been charged with offences including breaching lockdown orders and assaulting police after being pulled over on Thursday night.
