Ann58 Are you comfortable with shopping online? I just tried the Kmart website and put in the search term "surgery" and a few appeared.
I ordered the two pack with the zip front from Kmart after I had some difficulty doing up the Berlei post surgery bra that my breast care nurse ordered for me. The Berlei bra was otherwise nice so if you have a breast care nurse they could organise a free one for you.
Depending on which end of the mountains you're in, Target in Lithgow will have similar post surgery bras.
And if you have smaller breasts (and maybe for larger breasts but I don't have personal experience :), a crop top bra might be just as good although it can be harder to put on in the first days after surgery if your arm movement is restricted like mine was.