If you are receiving your goods via the post you are considered the importer of those goods and these may be subject to Customs duty and Goods and Services Tax (GST).
Generally, all goods imported into Australia are subject to Customs duty and GST and are assessed for community protection risks. However, all goods (except for tobacco and alcoholic beverages) may be imported duty and tax free if the value of the goods is A$1000 or less.
Irrespective of how your imported goods arrive in Australia, you will be required to lodge a formal Customs Import Declaration if their value is above A$1000, and pay the calculated duty and taxes. Import Declarations are used to clear goods from Customs control. Import Declaration may be lodged electronically, documentarily or through the use of a licensed Customs Broker (located in your local yellow pages). There are cost recovery charges associated with the lodgement of an import declaration.