澳洲机场退税是退前28天的税还是前30天的？

可以,官文原文如下: About the Tourist Refund Scheme (TRS)
The TRS enables you to claim a refund, subject to certain conditions, of the goods and services tax (GST) and wine equalisation tax (WET) that you pay on goods you buy in Australia.

To claim a refund you must:

•Spend $300 (GST inclusive) or more in the one store and get a single tax invoice
•Buy goods no more than 30 days before departure
•Wear or carry the goods on board the aircraft or ship and present them along with your original tax invoice, passport and international boarding pass to a Customs Officer at a TRS facility
•Claims at airports are available up to 30 minutes prior to the scheduled departure of your flight.
•Claims at seaports should be made no earlier than 4 hours and no later than 1 hour prior to the scheduled departure time of the vessel.
The refund only applies to goods you take with you as hand luggage or wear (unless aviation securi