Basically foriegners cannot get into Australia.
Unless they can prove it is essential big business.
There are limited places in hotel quarantine and hence the number of arrivals with a strong preference to only allowing Australian citizens/ permenant residents and their dependants a top priority. So effectively traveling to Australia for a holiday is a no go unless yes from NZ.

I just can't wait and hope this vaccine for the most part sorts out the need for quarantine and we get back to atleast some partial normality.