West Australian Premier Mark McGowan has tested positive to COVID-19 while isolating at home with his family.
Mr McGowan had initially returned a negative test after a family member contracted the virus, rendering him a close contact.
In a statement, the premier said he had taken another PCR test on Thursday and it had come back positive.
"It is not surprising considering one of my family members is positive," he said on Friday.
"In accordance with the protocols, this will extend my quarantine period until I am hopefully cleared to leave home next Thursday afternoon, at the earliest.
"I will continue to quarantine and work from home over this period."
The premier is scheduled to attend federal Labor's election campaign launch in Perth on May 1.
Federal Labor leader Anthony Albanese also tested positive to the virus this week.
Mr McGowan did not provide any details on his condition but thanked staff at testing clinics.
"I would also like to acknowledge the vital contribution of our committed health workers who have not only cared for my family, but also the many Western Australians who have been affected by this virus," he said.
WA last week moved to the national definition for close contacts, requiring only household members and intimate partners to isolate.
Strict proof of vaccination and mask-wearing requirements remain in place.
