That could definitely happen.
If so, you'd expect the Australian Government to immediately advise the global community of this newly found virus, enact the Biosecurity Act 2015, commission the top medical professionals and virologists available to investigate and when it's under control, conduct an independent and transparent inquiry to establish exactly how it happened and to prevent it happening again.
Compare this to what actually happened in China:
1. The CCP sat on the discovery of COVID-19 in Wuhan for weeks enabling them time to source PPE from all over the world, including 90 tonnes from a Sydney based Chinese company which was flown to China in a chartered plane. Not only did the delay result in the deaths of hundreds and thousands of people worldwide, once the CCP finally announced the existence of the virus, China had PPE, but other countries were left with bugger all.
2. Chinese doctor Li Wenliang was silenced by the CCP for sending a message to fellow medics warning of a virus he thought looked like Sars - another deadly coronavirus. This was in DECEMBER. He later died from COVID-19
3. Instead of agreeing to an independent inquiry into the origin of COVID-19 and how this can be prevented from happening again, the CCP spits the dummy, plays the race card, threatens trade sanctions, and gaslighted (or gaslit ?) that it in fact originated in the USA.
So yes viruses don't have passports, but you can bet your dollar that if it originated anywhere else, it would be handled a damn sight better than how the CCP handled it.