Great to have you on-board and welcome :)
I would say that the most ideal for your set-up would be finding a supplier in Australia as in Dropshipping - the faster the goods will be received by your buyer, the better! While finding a local supplier would actually mean lower costs, it might be a challenge to find a dropshipper in Australia for particular products. In case, an Australian dropshipper is unlikely to be a favorable supplier, I would suggest to do either:
1. Find a dropshipper in the neighboring continents such as Asia so, shipping time would not be a question. In the Link hidden: Login to view, 75% of the suppliers actually ship worldwide including Australia and most of the best deals come from Asia specifically China. They offer almost all types of products and usually has an established system for dropshipping.
2. Negotiate with Australian suppliers(preferably wholesalers) if they can dropship for you. Dropshipping is not as popular in Australia compared to the other countries however, that does not mean that these suppliers are not open to that set-up. You can establish a relationship with a local supplier and try to negotiate with them if they are keen to dropship for you.
Tip: You can start building trust and relationship with the supplier by doing sample orders just so you can gain their trust that you want to move forward with your business with them. This way, it might be easier to negotiate with them.
Hope this helps! :)