Western Australia will close its border to Victoria from midnight tonight following an outbreak of coronavirus cases in Melbourne.
From 12.01am Friday, January 1, only exempt travellers will be permitted into WA.
Anyone who arrived in WA from Victoria from December 21 will need to self-isolate immediately for 14 days and undergo a COVID-19 test on day 11 of quarantine, or earlier if they develop symptoms of the virus.
"Given the evolving situation in Victoria, Western Australia needs to move quickly and responsibly to protect our State from COVID-19 entering the local community," Acting Premier and Health Minister Roger Cook said.
"Like we have seen in Victoria, New South Wales and South Australia - an outbreak can get out of control very quickly and we cannot afford to hesitate.
"I understand this is going to cause many problems for many people, but we need to take this course of action to protect all Western Australians.
"We also need everyone who arrived from Victoria since December 21 to immediately go into self-quarantine.
"These people will only be released from self-quarantine, once they have completed 14 days in WA and they have had a COVID-19 test on day 11 of their stay here.
"If you have come into contact with someone who recently arrived from Victoria, you only need to be tested for COVID-19 if symptoms develop."
On Thursday, Victoria recorded five more cases of COVID-19 bringing the total number of cases to eight.