Edit 2: Altomic (below) found it cheaper again, ~AU$26 delivered from aliexpress:
https://www.aliexpress.com/item/32867072989.html
Edit: derdew (below) found it cheaper on Ebay, $31.99 from an Australian supplier, with AU plug, using code POLAR20:
https://www.ebay.com.au/itm/352648644849
One of the best smart chargers. Faster than Nitecore D4/I4, selectable charge current 300/500/700/1000mA. Charges NiMh (e.g. eneloop) batteries, and will charge 14500 and 18650 lithium-ion batteries too. Not suitable for LiFeP04 batteries. Charges 1-4 batteries, you don't have to charge your batteries in pairs.
This one comes with a plugpack, but Australian plug isn't an option. I recommend you choose the UK plug version, as it is more stable on most mains plug adapters.
Note that you will need to purchase a mains plug adaptor, if you don't already have one.
Also comes with a 12V car cable (cigarette lighter plug), if you want to take it on a camping trip. Or in case you are driving to a wedding, and just discovered your camera flash has flat batteries.
If you're comparing prices with Ebay prices, note that some Ebay sellers provide this charger WITHOUT the mains adaptor, and don't forget to add GST to the Ebay prices.
If you're wondering "why buy this one instead of a cheaper one", this charger lets you test your batteries, so you know how much capacity is in them, and you can recycle the dying batteries at Aldi.
For AA NiMh batteries of 2000mAh (standard Eneloops), I recommend a charge current of 700mA.
For AA NiMh batteries greater than 2000mAh, I recommend a charge current of 1000mA.
For AAA NiMh batteries I recommend a charge current of 300mA.
Review of charger here: http://budgetlightforum.com/node/61834
I'm not responsible for anyone using this advice:
I normally just get the US Plug version and twist the Prongs, it's the same distance between them and an AU plug so it goes in easily once they're twisted. All adapters are; are two bits of metal in the appropriate config, it doesn't do anything special.