FATbit Technologies is a leading development company that has majority of its clients for Australia. Although the company does not have a head quater in Australia but it works for global clients.
https://www.fatbit.com/?=pc

The efficientcy of the company is what makes me recommend it, as it has more than 20 specilized software designed to cater differnt niches/businesses like eCommerce, grocery business, food delivery, rental business, eLearning etc:
I am sharing a link where all the software offered by FATbit Technologies are mentioned:
https://www.fatbit.com/multivendor-ecommerce-marketplace-platforms.html?=pc