The thought had occurred to me to burn 4,500 Avios points on a SYD-MEL award in order to have an ongoing QF BP; however, I see no SYD-MEL flights departing from the International Terminal. (There used to be a few domestic flights which departed from SYD's International Terminal...I guess that is history.) In any event, based upon the above posts, it seems like it might be a possibility (as long as I book an award flight SYD-MEL) to use the domestic QF 1st Class or Business Class lounge, until EY opens up its lounge for its evening flight.
Any thoughts/suggestions (especially those that are experience-based) would be greatly appreciated.
You would not be able to access the QF First Lounge without an onward oneworld boarding pass from the international terminal.
Booking a SYD-MEL flight would allow you to access the QF Business (Emerald) lounge and Qantas Club (Sapphire) lounge in the domestic terminal, however you would need to transfer to the domestic terminal and then back from there to the international terminal.
Why not go into Sydney for the day? You can be in Circular Quay in around the same time as you would be in the domestic business lounge..