Quoted from Australian Customs
Imported goods valued at or below A$1000
Generally, there is no requirement to pay duty and Goods and Services Tax (GST) on imported goods valued at or below A$1000, except for alcohol (refer to Example 2 where Wine Equalisation Tax (WET) is also payable) and/or tobacco products (refer to Example 4).
Imported goods with a value at or below A$1000 that arrive by air or sea cargo will require a self-assessed clearance (SAC) declaration to be lodged with Customs and Border Protection.
There are no Customs and Border Protection charges for making a SAC declaration.
For more information about SAC declarations see the fact sheet Self-assessed Clearance (SAC) Declarations.
Goods with a value at or below A$1000 that arrive by post do not require a SAC declaration.
For more information on goods that arrive in Australia by post click on importing goods by post.
Imported goods with a value above A$1000
If your imported goods arrive in Australia by air cargo, sea cargo or by post and their value is above A$1000, in most cases, you will be required to make an Import Declaration and pay the calculated duty and taxes.
An Import Declaration is a statement made to Customs and Border Protection providing information about imported goods.
There is a Customs and Border Protection import processing charge for making an import declaration. Information on Customs and Border Protection fees and charges is available in Australian Customs Notice 2006/21.
For more information about import declarations see the fact sheet Import Declarations.
Imported goods may also require clearance from Australian Quarantine and Inspection Service (AQIS). More information on AQIS requirements is available at
www.daff.gov.au/aqis
Example 3:
An importation of goods (other than tobacco products or alcoholic beverages) valued above A$1000
A$
Customs value (Cval) = 2000.00
Customs duty (Duty) @ 5% of Cval = 100.00(Payable)
International transport and insurance or postage (T&I) = 150.00
Value of the Taxable Importation (VoTI) (Cval+Duty+T&I) = 2250.00
Goods and Services Tax (GST) @ 10% of the VoTI = 225.00(Payable)
Total payable Duty + GST = 325.00
http://www.customs.gov.au/site/page5549.asp#Duty