Only certain partner flights appear when searching with QR Avios, but you can book pretty much any Oneworld airline using BA Avios, and of course, you can transfer between at 1:1.
So if your only point balance is Avios and there's absolutely nothing from Australia, you might consider using BA Avios to get from Sydney - Singapore, have a lovely stop in Singapore, and then use QR Avios to get from Singapore to Europe. You might also consider using BA Avios on MH to KUL, or perhaps CX to HKG, then QR onwards. You can also book these partners using QR Avios, although you'd have to call up as not all Oneworld partners show up on QR, while on BA they do online. You'd have to book separately though, hence why I'd say have a stopover.
It's going to cost more than simply 90k direct to Europe though, but if you're stuck, it's an option. Cancellation fees for both QR and BA are minimal at best, so you could secure flights now, and then wait and see what pops up - at worst, you have a 2 stop solution to Europe on some great airlines. At best, you pay a small cancellation fee and you book QR from Australia.