Contact cajon makers directly to find cajons made in Australia. Unfortunately most big online retailers and many music stores only carry imported brands. Buying a locally made cajon cyles your income back through your local economy. Below are links to 10 cajon makers in Australia:

You can find out who makes the best cajon for you in Australia by checking out the links on this page. These cajon builders are found in various locations in Australia, you'll need to chat with them to find one nearest you. It may be a bit more effort but it is nice to contribute to your local economy. I'd start with Arc, Rockbox, Custom and Tassie.

Minimize the carbon footprint of your cajon purchase - buy a locally made cajon directly from the cajon builder. Most imported cajons are shipped around the planet in big cargo ships. A locally made cajon helps your local economy and demonstrates that you are thinking about and helping local craftsmen.

YouTube playlist of cajons made in Australia:
Note that not all manufacturers have current YouTube videos. The list on this page includes websites and Facebook pages which may contain videos not on YouTube. The list on this page is actively maintained, the YouTube playlist is less frequently updated.

One photo per Australian manufacturer in Pinterest:

Listed above are links to the cajon drum builders in Australia as retrieved by Internet searches in March 2018 to March 2020. I am sure there are many others not listed. Please send me updates and correction if you have additional information. Thanks.