At Hervey bay where I was recently, everyone bar QantasLink (Sunstate) passengers were screened, but QantasLink passengers can carry an AK47 under their jumper on board and enter Brisbane etc. However from memory, to "re-enter" the domestic terminal at Brisbane, security screening is required as it's a seperate area.
RPT turboprop services remain unscreened under the regs, so does jet charter...it's all a bit crazy especially as jets (ERJ-170) are getting smaller and props (Q400) are getting bigger. And theres a lot of jet charter flying into major airports unscreened. All of which the department is apparently "looking at"...