The new case is a fully vaccinated 48-year-old Katherine man, who is a household contact of case number one in the territory’s most recent outbreak of the virus.
Chief Minister Michael Gunner said the man had been isolating for his entire infectious period, having returned two negative tests while in isolation before getting a positive result.
The man has mild flu symptoms.
Mr Gunner on Tuesday said Greater Darwin’s lockout would be lifted at midnight after all traces of the virus had been thoroughly tracked across the territory.
“We can move out of the Greater Darwin lockout with confidence tonight knowing we have traced and tracked this virus,” he said.
The news came after the lockout was extended for 24 hours, having originally been meant to end last night.
It is still mandatory to wear a mask everywhere in Greater Darwin and Katherine until 5pm on Friday.
From then, masks will still be required to be worn inside and when people are not able to physically distance.