1943 S. J. BakerPop. Dict. Austral. Slang (ed. 3) 64Ratbag, an unpleasantly disposed or vicious person: a term of contempt, though not always offensive. Whence, ‘ratbaggery’.
2006 Northern Territory (Nexis) 22 Sept. 6 There is an element of ratbaggery going on we will no longer tolerate.