Additional Sales Tax on eBay Australia
Know when extra eBay tax may apply
Sales Tax on eBay Australia Orders
The Sales Tax added onto eBay orders (overseas/international) is added directly by eBay at the time of payment.
Please contact eBay directly for more information this.
This Taxes and import charges article on eBay explains in more detail:
https://www.ebay.com/help/selling/fees-credits-invoices/taxes-import-charges?id=4121