I think Bali will be one of the last places on earth that Oz open up to.
Why? The Island can easily be controlled, in fact the local authority there is talking about a bubble around the resort area of the island.
I would think the US, India and Brazil are probably more risk.
https://www.worldometers.info/coronavirus/
Surely one criteria for international destinations to open as "bubbles" is direct flights, no transit. So the Perth to London flight would be great except the UK is awash with Covd19.