I did some more research, and you guys have ADI, which was purchased by Thales (some giant French conglomerate), and it sells some guns and commercial ammunition through Australia Munitions (guns as Lithgow Arms and ammo as Australian Outback). The guns seem to just be short action, and the rifles seem to be limited to military rounds (223/308).
I spent a little time to see if Australians are prohibited from civilian manufacturing of rifles, cases, bullets or cartridges, and it doesn't seem like it, but I read somewhere that Australia "nationalized" munition production in 1989 with the creation of ADI as a government owned corporation (couldn't find any mention of this beyond Wikipedia).
I wonder how one would go about finding old case/bullet/cartridge manufacturing equipment. It sounds like Footscray, Victoria was the center for small arms ammunition manufacturing during WWII, and has had a number of plants closed down as production needs wound down.