So this is incorrect?
https://intas.com.au/importing-business-goods-australia/
The import duty is based
on 5% of the value of your goods converted to Australian dollars. To calculate the GST on imported goods, add the value of the goods in Australian dollars, plus freight, insurances and the import duty. The 10% GST is calculated on this total.
Edit: This example is incorrect?
For example, if you purchase jewellery for AUD$500, add the 5% customs duty $25 plus the cost of freight and insurances, say at $42. This gives a total of $567 plus a 10% GST of $56.70. The total cost of goods equals approximately $623.70.