The Northern Territory has declared Melbourne Airport's Holiday Inn a COVID-19 hotspot as a cluster linked to the quarantine hotel grows by two.
Another worker and former guest of the Victorian hotel were diagnosed late on Wednesday, bringing the total number of cases linked to the outbreak to eight.
The two new infections mean the outbreak now encompasses three workers, two released guests and a family of three no longer staying at the hotel.
People who arrive in the NT from 4pm who have been at the Holiday Inn will be required to go into supervised quarantine, or they can return to Melbourne.
Anyone who arrived in the NT between February 5 and 4pm on Wednesday are advised to have a test and undertake self-quarantine until a negative test result is returned.
NT Chief Health Officer Hugh Heggie said the decision was made based on information the Australian Health Protection Principal Committee released on the situation in Victoria.
"This has also led to the decision to treat the Holiday Inn Melbourne Airport as a hotspot as the known point of infection for this emerging Victorian cluster," he said.
Earlier, the Melbourne suburb of Sunbury was added to the list after two virus cases linked to the hotel were diagnosed on Tuesday.
Maidstone, Sunshine and Taylors Lakes in city's northwest were listed as hotpots on Monday.
Travellers to the NT can still transit through Melbourne's Tullamarine Airport.
The Holiday Inn has been closed until further notice for cleaning as contact tracing continues.
About 135 staff at the hotel were stood down on Tuesday night.
They were told to get tested and then isolate at home for 14 days, bringing the total number of staff isolating to 220.
Forty-eight guests of the hotel considered primary close contacts were transferred to the Pullman Melbourne to quarantine.
The NT has recorded 103 COVID-19 cases. All have been quarantine facilities.