Depending on the duration of your stay and if you are sharing the data plan to other devices, you could consider the following.
Amaysim
https://www.amaysim.com.au/mobile-plans.html
Hotspot function allowed on iPhone. If need data only or more data, can recharge more data into the mobile plan.
http://www.amaysim.com.au/mobile-pla...broadband.html
Another option is Optus $2 dollar days plan which offer unlimited voice and data. Hotspot disabled on iPhone. But, hotspot was reported to be working on Android phone, e.g. SGS3.
https://www.optus.com.au/shop/prepaidmobile/2dollardays