Victoria has declared the Perth and Peel regions "red zones" under the state's traffic light travel permit system, effective 2am on Saturday.
Victorians returning home from Perth and Peel have to quarantine at home for 14 days, and non-Victorians will have to go into hotel quarantine until a return flight is arranged.
The state's Chief Health Officer said anyone in Victoria who has been in the Perth and Peel regions between April 17 and 23 must isolate, get a test within 72 hours and isolate until a negative result.
Those updates follow warnings earlier today about potential exposure to a COVID-positive case on a Qantas flight to Melbourne and at Melbourne Airport.
Passengers on Qantas flight 778 from Perth to Melbourne on Wednesday, April 21 have been told to get tested and isolate for 14 days regardless of their result.
Anyone who visited the Qantas terminal (terminal 1) at Melbourne Airport between 7pm and 7.30pm on Wednesday, April 21 must get tested and isolate until they get a negative result.
The airport time frame has been narrowed since earlier advice from the Department of Health.