https://www.bleepingcomputer.com/news/technology/amazon-blocks-australian-shoppers-from-us-site-because-of-new-tax/

Amazon announced plans to block Australian users from ordering from its main US store (Amazon.com) and will redirect customers to its local Australian site (Amazon.com.au) instead.

The move comes after the Australian government has expanded a local tax named the Goods and Services Tax (GST) to online goods shipped into the country. The GST will impose a 10% fee for all online goods imported into Australia, worth less than A$1,000 ($756).