Australian operators don't carry alternates as a matter of course.
If the weather is fine, alternate airport required only if the weather is below the Alternate Weather Criteria? (400ft cloud base / 2km vis, something like that)
Probably Brisbane, Melbourne, Adelaide for widebodies. Canberra, and maybe Williamtown for 737's, A320's, B767's etc.
Richmond, Nowra, East Sale plus all the above available for Emergencies.