Biante produce models of Australian cars and racing models. The quality is excellent and scales are 1:64, 1:43 & 1:18.
They are also distributors for other manufacturers, including Minichamps, AutoArt, Spark, CMC, Kyosho, Redline and Sunstar, which gives them a range of vehicles from all over the world.
You can order direct from the website (I have done this, and the service has been good, but, of course, you pay freight as well, although its reasonable).
The other option is to order from one of the many distributing retailers all around Australia. This is probably better, because some models sell out very fast on the website, so a pre-order via a model shop should prevent you missing out on the model, and you dont have the freight cost, either.
The model shops that stock their products are listed on the website.