Chief Minister Michael Gunner has warned the crisis in the remote Indigenous community of Robinson River and the town of Katherine is not over after 19 infections were recorded in three days.
"There were no new positive cases in the NT overnight," Mr Gunner told reporters on Thursday.
"This is good news, but it is not a day to get ahead of ourselves."
He said people should not assume the outbreak is under control and the virus trapped.
"This is Delta, it's in large vulnerable households. We're not out of the woods," he said.
Genomic test results released late on Thursday confirmed the current cluster is linked to the NT's first case of community transmission earlier this month.
That was triggered by a 21-year-old woman who unlawfully travelled to Darwin from Cairns after visiting Victoria, where she contracted the virus.
She infected a man in Darwin as the virus spread to two others in Katherine before authorities declared they had control of the outbreak on November 9.
But that was short lived with the same strain of virus now found to be responsible for the current cluster in Katherine - 320km south of Darwin - and Robinson River.
That outbreak started on Monday when a 30-year-old woman and a 43-year-old man from Katherine were reported to be infected.
The woman was unvaccinated and travelled from Katherine to Robinson River - 1000km southeast of Darwin - where she tested positive, the first case reported in a remote NT Aboriginal community.
Nine new cases were detected in Katherine on Tuesday, including a 71-year-old man and a 65-year-old woman who was admitted to Royal Darwin Hospital.
Eight new cases were reported on Wednesday, with five infections diagnosed in Robinson River, including a three-week-old girl.
All those infected are Indigenous Territorians.
Health teams will concentrate on finding the missing links between the two clusters, with NT Health saying it now knows the virus was circulating in Katherine from November 4 to 13.
They've identified 384 close contacts, with 288 contacted and isolating, and 201 returning negative tests.
"There's also a strong chance of close contacts who have tested negative returning a positive test in coming days," Mr Gunner said.
"We still have lots of testing and tracing work to do, but things are looking more positive."
All 350 residents at Robinson River have been tested but many results won't be available until later in the week.
About 50 people from the community have been transferred into quarantine at the National Centre for Resilience.
"The best thing about no extra cases is the time it buys our tracing teams. It's a really important 24 hours that we've got now", Mr Gunner said.
Greater Katherine and Robinson River were plunged into a three-day lockdown when the first cases were announced on Monday.
That has since been extended to seven days, with a territory-wide order to wear face masks in most public areas.
Across the NT, 96 per cent of people over 16 have had their first vaccine dose and 83 per cent are fully vaccinated, according to recent NT Health statistics, which have been criticised for being inflated by about 10 per cent.
In remote communities, 77 per cent of people over 16 have had their first jab and 62 per cent are double dosed.
In Robinson River, 89 per cent of residents have received their first dose and 79 per cent have had two jabs.
Up to date vaccination statistics for Katherine River have been requested from the NT government.
Meanwhile, Health Minister Greg Hunt has extended a biosecurity zone in Robinson River and surrounding homelands to November 22.
Under federal law it's illegal for people to enter or leave the area.
12°C