Green’s Dictionary of Slang

(Aus.) one who accepts bribes.

1877		S. James Vagabond Papers (3rd series) 138: The warder who overlooks these little things, and who will make presents of tobacco, or traffic, is called a ‘sugarbag’. I expect I was about the sweetest sugarbag they have had in Pentridge for a long time.
1924		Aussie (Sydney) Mar. 34/1: Th’ game’s right enough [...] w’ere yer’as the same camp an’ as a sugar-bag of a ganger, an’ can go slow a bit [AND].
1925		Smith’s Wkly (Sydney) 11 Apr. 13/5: She's a ‘demon’s’ daughter. The hottest ‘sugarbag’ that was ever in the detective force. I dooked him hundreds of quids when I was in the ‘business’.
1950		F.J. Hardy Power Without Glory 444: You are playing the public for suckers. And you get away with it, because you have made sugar-bags of the men who should expose you.
1968		L.H. Evers Fall among Thieves 68: She knows that the copper who’s number one is a sugar-bag so she talks to him half cunning about a little something in his hand [AND].
1972		Berman & Childs Why Isn’t She Dead? 66: If a policeman is called a ‘sugarbag’ by other police or the underworld he is on the take. The sugar merely sweetens or lightens any offence [AND].