Hello Dayco,
Welcome to our wonderful and curious world of ABDL.
I can tell you there are a few places to purchase in Australia and they are as follows.
Littles-Downunder - Based in Brisbane Queensland Australia
https://www.littles-downunder.com.au/
MyABDLSupplies - Based in Sydney New South Wales Australia
https://myabdlsupplies.com.au/
Other than these great stores are there a number of Incontinence Stores but most of these are not ABDL aware and some don't offer discreet packaging.
I personally have also had great success on eBay and Gumtree buying products some people are happy to post and others aren't.
Hope that helps and drop me a line if I can answer any further questions.
Cheers Stay padded and enjoy the journey