Well, GST can apply to goods when a local entry is made, under the Customs Tariff Act, so in a very real sense it is an import tax. It never used to apply to low value imports by post into Australia until legislation to change that was implemented a couple of years ago. You can thank Gerry Effing Harvey for that.
It's still possible to import photographic equipment into Australia without duty (if applicable) or GST if the customs value is under $1000. Under the low value scheme selling platforms such as eBay or Amazon are required to collect GST. Private businesses overseas have to collect and remit it *if* their annual sales to Australia are over the threshold for registration. B & H for instance, will now add GST on.
But if you purchase goods directly (Ie not off eBay) from a seller who does not make enough volume of sales to Australia to register under the low value scheme, they won't have to collect GST. And—when local entry happens into Australia, if the customs value is under $1000, the postal exemption from time immemorial provided under Schedule 4 of the Act is still in place—meaning GST and duty will be waived. No GST at time of purchase; and no GST on importation, entirely legally.
A couple of months ago I purchased a Leica IIIf for $300 from an overseas seller who is beneath the registration threshold. On importation into the country, and delivery to my Tasmanian address, GST was quite legitimately not required to be paid. In short, another great reason to purchase off-eBay if possible.