Green’s Dictionary of Slang

(Aus./N.Z.) the police; prison officers.

1950		S.J. Baker in Sun. Herald (Sydney) 8 June 9/5: Detective Doyle has about a dozen rhyming slang words in his list. For example: [...] ‘ducks and geese,’ police.
1967		‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xxxiv 4/4: ducks and geese: Police. Shortened to ‘duck and’.
1983		R. Aven-Bray Ridgey-Didge Oz Jack Lang 7: She was thinking of her lazy silvery moon, the ducks and geese, and the cost for the use of the drum in the cracker joint she operated from.
1990		Tupper & Wortley Aus. Prison Sl. Gloss. 🌐 Ducks and geese. Rhyming slang for police.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 62/2: ducks and geese n. the police; prison officers.
2002		Pete’s Aussie Sl. Home Page 🌐 ducks and geese: the police.