A three-week-old baby girl is among the six new Covid-19 cases reported in the Northern Territory.
The new cases bring the total number of a cluster between Katherine and Robinson River to 19.
"The situation of both Robinson River and Katherine is serious," NT chief minister Michael Gunner told reporters on Wednesday.
"We know how quickly Delta can spread within households, and we cannot be sure yet that it has not spread further into the Robinson River and Katherine communities, or wider in the Territory."
Mr Gunner continued to urge residents to get vaccinated.
"If you waited because you didn't think Covid would get here, it's here. If you waited because you didn't think Covid was serious, you're wrong," he said.
"The vaccine is your best defence."
Five of the infections diagnosed are in the remote Indigenous community of Robinson River and one case is in Katherine, 320km south of Darwin. All of them are Aboriginal Territorians.
'Importance of checking in'
Mr Gunner reminded people of the importance of checking in to venues to allow contact tracers to trace close contacts.
"To every venue out there, the check-in is important," he said.
"Please make sure that everyone who enters your premises checks in, that their details can be used.
"We've hit quicksand because of the failure to ensure if people are checking in their details can be used in an emergency situation such as this."
Greater Katherine and Robinson River were plunged into a three-day lockdown on Monday evening.
Mr Gunner said it was likely but not confirmed that the cluster was linked to the NT's first community transmission outbreak, which was triggered several weeks ago by a woman who unlawfully travelled to the NT from Cairns after visiting Victoria.
Genomic testing results to confirm this are due on Thursday.
Close contact sites:
Katherine District Hospital emergency department (waiting room only), Monday, 15 November, 2:20pm to 2:50pm
Katherine District Hospital (emergency department only), Saturday, 13 November 12:05am to 3:00pm
Katherine District Hospital (emergency department, waiting room only), Friday, 12 November, 9:30pm to 10:30pm
Katherine District Hospital (emergency department only), Friday, 12 November, 11:00pm to 11:59pm
Katherine District Hospital (outpatients' department only), Thursday, 11 November, 1:45pm to 4:00pm
Kirby's Pub, Katherine Hotel, Friday, 12 November 12:00pm to 4:30pm
The Wurli clinic on Third and 15th street, Monday, 13 November, 1:00pm to 3:00pm
Captain Jack's Fish and Chips Monday, 13 November, 12pm to 12:35pm
The Wurli Wurli main clinic on Third Street, Monday, 13 November, 10:00am to 1155am
Casual contact sites:
Katherine Woolworths, Saturday, 13 November, 3:00pm to 4:00pm
Katherine Woolworths, Saturday, 13 November 5:35pm to 6:00pm
Katherine Woolies Friday, 12 November 5:00pm to 6:00pm
Katherine Salvos, Saturday, 13 November 10:00am to 11:00am
Better Home Living, Saturday, 13 November 9:35am to 9:45am
K-Hub, Saturday, 13 November 4:00pm to 4:30pm
Katherine Dollars and Cents, Saturday 13 November 4:00pm to 4:30pm
Katherine McDonald's Saturday, 13 November 11:05am to 11:30am
Katherine Public Library, Friday, 12 November 1:30pm to 2:30pm
BP Katherine, Friday, 12 November 1:35pm to 1:45pm
Captain Jack's fish and chips, Thursday, 11 November 2:14pm to 2pm and 13 November to 2pm to 2:30pm
East Side Mini Mart, Thursday, 11 November 6:00pm to 6:30pm
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