Upvote:3
Well yes you can in theory.
There may be only one currency exchange inside the departure area after passing security. On March 22, 2020 I asked and they said there wasn't another, and I didn't see another. I didn't see any in the main area around the check-in desks, but I didn't look thoroughly.
But at this time of Covid 19, the one exchange had no Australian dollars left. They also didn't have quite enough US dollars for me. I bought Euros.
Upvote:4
Yes, it's likely that Australian dollars will be available at any given exchange counter. They won't have small denominations, so your change will be in local currency. Hit the exchange counter before you hit the duty free shop (which will take your change as partial payment).
Airport currency exchanges always, always gouge you, no matter if you're in "the poorer country". Exchanges in the city will give you somewhat better rates. For the future, it's best to use debit and credit cards where possible when traveling; assuming you don't have a crap bank the charges will be much lower than even a reasonable city center foreign exchange counter.