Prior to the shock house party revelation, Prime Minister Scott Morrison had urged Queensland not to overreact in the wake of two cases of community transmission, saying it would put at risk Australia's world-leading economic recovery.
The Greater Brisbane area is being plunged into a three-day lockdown, with four more community transmission cases diagnosed overnight.
"Due to the evolving COVID-19 situation in Queensland, additional steps are being taken to keep WA safe", Mr McGowan said in a Facebook post on Saturday night.
Queensland's Chief Health Officer Jeannette Young said it was not known how the man contracted the disease and that genomic sequencing was being conducted to determine the source.
"We would like to rule out every single possibility here; the sooner that everyone does this (get tested), the better we will be", she said.
"We won't have absolute proof about this new case because he doesn't have any virus that we can sequence - but it is highly likely", she said.
"Her sister is also positive".
NSW Health is contacting more than 20,000 travellers who have arrived in the state from Queensland between March 20 and 26.
Victoria has mandated that anyone who has entered the state from Brisbane and Moreton Bay since Friday, March 12 needs to immediately self-isolate, get tested within 72 hours and stay isolated until they receive a negative result.
"The Queensland Government has announced two people who have tested positive for COVID-19 were in Byron Bay while infectious", Byron Shire Council said in a post on social media. "But, I don't think they'll have had enough chance to spread that within the community further, so the risk of further spread is low, I would assume, and that's a good thing".
Chief Health Officer Jeannette Young is scheduled to brief the Premier about the unfolding emergency today and further announcements are expected.
"I know it is really tough".
Aged care facilities, hospitals and prisons will have visitor restrictions brought in, while all pubs and restaurants must ensure that patrons are seated.
Officials say it's likely the 26-year-old had numerous interactions at the venues as he spent considerable time at both, increasing the likelihood of transmission.
"It was important information that we put out, based on the facts we had at the time, because if we had not, and that had gone out in some other way, then we would not be transparent about what we knew".
The Prime Minister has agreed to halve our global arrivals into hotel quarantine as well. "I don't want to see that happen to Queensland, I don't want to see that happen to Australia".
- Procession honors fallen officer Eric Talley in Boulder King Soopers shooting
- Colorado shooting: US President Joe Biden calls for gun control
- Severe storms possible Thursday afternoon/evening
- Suez Canal blockage could affect United Kingdom auto deliveries
- European Union moves toward stricter export controls for COVID vaccines
- Ontario ICU capacity reaching critical level because of COVID-19: OHA
- Cumulative number of Covid vaccine doses given crosses 5.46 crore: Government
- Biden keeps returning to Trump as a cause of nation’s troubles
- Georgia Gov. Brian Kemp signs sweeping election rule changes into law
- Just how important is the Suez Canal to global trade?