“The companies which produce these sorts of goods often don’t ship directly to Australia, or shipping is prohibitively expensive,” she said. Amazon’s international site, she added, “has the infrastructure to be able to ship them at affordable prices.”

Amazon has tried to convince customers that the change won’t inhibit their ability to shop. They told customers that the Australian site had more than 60 million products, and tried to soften the blow by offering a $20 gift voucher to amazon.com.au.

But customers were quick to point out that this was a far cry from the hundreds of millions of products they could browse on Amazon’s main site.

Emma Shaw, a musical theater performer, said she was likely to have a hard time finding hard-copy albums for Off Broadway shows like “Spamilton” on the Australian site.

Some have accused the Australian government of using the tax to cut down on imports. But Dr. Jim Minifie, an economist with the Grattan Institute, an Australian research organization, said the government was merely trying to make sure overseas-based online retailers didn’t gain an unfair competitive advantage.