The Northern Territory’s daily COVID-19 case tally has jumped to 60 infections as the territory adopts the new national definition of a close contact.

New isolation and testing rules have been rolled out along with a mask mandate from 6pm on Friday, putting a dampener on New Year’s Eve celebrations for many.

“In the past 72 hours there has been a growing trend of community transmission,” Chief Minister Michael Gunner told reporters on Friday.

“We had one case of community transmission on Wednesday, four cases … yesterday and we have at least 11 cases of community transmission today.”

The jump in infections comes as the NT adopts Thursday’s national cabinet definition of a close contact, which is now classified as someone who has spent four hours or more with a confirmed case in a household or household-like setting.

“You’ve got to put your resources where they are most needed. Close contacts are the biggest danger and essentially they’re in households,” Mr Gunner said.

The rules for isolation and testing have also been relaxed with positive cases now only required to isolate for seven days so long as they return a negative PCR test on day six.

Fully vaccinated close contacts continue to be required to isolate for seven days but the testing requirements have been eased.

Unvaccinated positive cases and close contacts must isolate for 14 days and take a COVID-19 test on day 12 of their quarantine period.

The NT has also streamlined its COVID-19 exposure site alert system, with generic texts to be sent to people who checked into sites where a positive case has visited.

“The changes mean workers won’t be prevented from working unnecessarily,” Mr Gunner said.

Meanwhile, more than 30 of the new cases are infected interstate arrivals or people who were close contacts of previous cases.

Another six cases are linked to a regional Delta outbreak that continues to spread in Katherine, 320km south of Darwin, and Tennant Creek, 510km north of Alice Springs.

The status of another 15 cases is yet to be determined.

The majority of the community transmission is in Darwin.

“While we presume all regional cases are Delta we presume interstate arrivals and their close contacts are Omicron,” Mr Gunner said.

The chief minister also announced a mask mandate from 6pm on Friday for all public indoor venues across the territory.

It applies when people cannot socially distance and are not eating or drinking.

It also includes public transport.

“I know the timing of the mandate is not ideal coming into New Year’s Eve,” Mr Gunner said.

“You can still go out. We want you to go out. We want you to have as much fun as you can but we need you to do this as safely as possible. Mask up.”

Twenty-four people with the virus are in NT hospitals but none are in intensive care.

-AAP