The Northern Territory has declared parts of Melbourne as COVID-19 hotspots after a hotel quarantine worker linked to the Australian Open tested positive for the virus.
The 26-year-old man was diagnosed on Wednesday, five days after he completed his last shift at Melbourne's Grand Hyatt hotel, as part of the tennis tournament's quarantine program.
Ten suburbs have been declared hotspots from 3.30pm ACST on Thursday.
These are Melbourne, West Melbourne, Brighton, Clayton South, Heatherton, Keysborough, Moorabbin, Noble Park, Springvale and Wheelers Hill.
People who arrive in the NT from the hotspots will be required to go into supervised quarantine, or they can return to Melbourne.
Anyone in the NT who has been in one of the hotspots since January 29 will have to isolate until they receive a negative test result.
Chief Minister Michael Gunner says travellers from Melbourne will be met and interviewed by health teams.
"When it comes to the coronavirus, no one ever regrets being too careful," he told reporters on Thursday.
He said Victoria had responded quickly to the outbreak and he was confident the hotspot declarations would not be needed for long.
"But given how infectious these new strains are, it's best to go hard and be extra cautious until we know more," he said.
Chief Health Officer Hugh Heggie said declaring individual suburbs hotspots was a targeted approach by NT Health based on the infected man's movement and places of potential exposure.
He urged all Territorians to take the risk of virus transmission seriously.
Two of the man's close contacts have tested negative, with Victorian health authorities reaching 19 more.
A further 600 casual contacts also have been told to isolate and get tested, as have 520 Australian Open players, officials and support staff.
Melbourne Park matches were suspended on Thursday but they're set to resume on Friday.
Australian Open director Craig Tiley said the tournament would go ahead as planned from next Monday.
More than 50 localities in metropolitan Perth, the Peel region and Western Australia's southwest remain hotspots for the purpose of travel to the NT.