Unlikely. Mercy and Comfort had issues as converted ships. I doubt anyone will go down that route again.Actually when I think about it the USN ships Mercy and Comfort are converted tankers and as it happens the RAN is just about to decommission HMAS Sirius. I wonder.
An Admiral From 100 Years Ago Warned Against Big Hospital Ships
Shipbuilders are urging the U.S. Navy to replace America's two massive hospital ships. But, rather than have the Navy blindly recapitalize, it may be better to explore doctrine from when hospital ships were regular fleet components. What can modern navies learn from the Golden Age of Hospital Ships?
www.forbes.com
The US Navy’s hospital ships in the COVID-19 fight badly need replacing
The ships helping fight the COVID-19 outbreaks in New York City and L.A. need replacing, but the Navy doesn't have a clear path forward.
www.defensenews.com
The Austal hospital ship, has some merit for a force like the US. They could scatter them globally, and have a fast deploying facility in or near theatre. That is different from Australia's needs. Australia wants something that can stay in region, do medical and other humanitarian missions.
Also a new local build is going to be very attractive.