Here's the relevant section of the Australian Budget 2017-18 entitled "Backing innovation and FinTech"
http://www.budget.gov.au/2017-18/content/glossies/factsheets/html/FS_innovation.htm

The Government will make it easier for new innovative digital currency businesses to operate in Australia. From 1 July 2017, purchases of digital currency will no longer be subject to the GST, allowing digital currencies to be treated just like money for GST purposes. Currently, consumers who use digital currencies can effectively bear GST twice: once on the purchase of the digital currency and once again on its use in exchange for other goods and services subject to the GST.