Information about Customs, GST, Duties and shipping to Australia contained herewith.
General Rule of Thumb
The rule of thumb to follow when ordering parts/items from overseas is that if you pay less than $1000AUD (the Customs Value - CV)) for the items exclusive of shipping, you will not pay duty and GST.
If your items are over $1000AUD, then you may be subject to GST and duty. Some members have received items that have been valued over $1000AUD and have not paid GST or duty; it is the luck of the draw. However, you are more than likely going to be stung with GST and duty.
Calculation of Value
Australian Customs may calculate the value of your items using a number of methods. Usually, you will not have to worry about any of the methods as your parts will usually contain an invoice with the amount that you paid for it from the vendor. This will suffice for Customs.
Internal and External Shipping
The exception to the general rule of thumb is shipping. Any costs associated with transport from the vendor to Australian shores is not included in the valuation of goods.
However, costs associated with transport inside Australia are included in the valuation of goods. The costs won't be much, but if you are edging towards $1000AUD then one of the following procedures may save you a large amount of money.
Splitting Shipments and Multiple Shipments
Some people think that it may be worth splitting shipments (ie: four tyres in two separate packages). You should be aware that Customs will combine packages sent from the same vendor to the same addressee and calculate them as one package.
One technique to get around this is to have the vendor list your business as the recipient as one, and your home as the recipient of the other. Customs may also check the name and vendor, but they are unable to combine the packages and treat them as one as Duty laws require the addressee and the vendor to be the same.
All you are doing here is avoiding the 'gotcha' clause that Customs have by having two different addresses.
Example of Duty - How is Duty and GST Calculated?
The Import Duty for your goods is calculated as a percentage of the price you paid for goods (CV). While some rates differ (tobacco, liquor etc.), the majority of goods attract a 5% duty rate.
Then, GST is calculated at 10% (normal rate) of the Value of the Taxable Import (VoTI). The VoTI is calculated by the addition of the Customs Value (CV) PLUS the Duty PLUS the value of the International Transport and Insurance (T&I).
An example of how the duty and GST is calculated on goods valued at AUD$1,500 which attract a 5% duty rate would be:
If the Customs value (CV) of your tyres = $1,500.00
Then the Customs Duty @ 5% of the $1,500 (CV) = $75.00 (Payable)
Assuming the international transport and insurance (T&I) = $125.00
Then the VoTI = (CV) + Duty + (T&I) = $1,700.00
GST = 10% of the VoTI = 10% x $1,700 = $170.00 (Payable)
Therefore the Total Duty plus GST payable = $245.00
Links
For more information on all this stuff:
Customs FAQ on Importing:
http://www.customs.gov.au/webdata/re...sbypostfaq.pdf
Detailed Customs info on Importing:
http://www.customs.gov.au/site/page5549.asp