Green’s Dictionary of Slang

(Aus.) a garbage man, a dustbin man.

1940		L.W. Lower Dly News (Perth) 28 May 18/5: Just call Him ‘Garbo’. Refainement [sic] has set in. A N.S.W. municipal council has decided that it is 'not nice' for a man to be referred to as the ‘garbage man’.
1953		Baker Aus. Speaks iv. 105: Garbo, a garbage man.
1967		‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xxxix 4/4: sanitary engineer: A garbo, a night soil carter.
1968		Western Herald Bourke, NSW) 19 Jan. 1/6: On Christmas morning [...] to the accompaniment of the rattle of garbage can lids their shouting and rejoicing could be heard as follows: ‘Garbos, Garbos, bring out your sherry, whisky or beer — anything will do’.
1971		F.J. Hardy Outcasts of Foolgarah (1975) 7: Pursuing their chosen career as scavenging labourers (self-styled Garbos for short) employed by the ratepayers of the Foolgarah Shire Council.
1982		N. Keesing Lily on the Dustbin 118: Not so long ago every suburban family had a ‘garbo’, a ‘dunny man’ and a ‘paper boy’.
1986		R.G. Barrett Real Thing 87: Garbos milling around in their beanies and football jumpers.
1999		G. Seal Lingo 78: In addition to the sanny man [...] there has been an ongoing need for refuse to be taken away from homes by the garbo – garbage-man and the bottle-o(h) who, in many though not all States, takes away the empties or dead soldiers.
2007		S. Maloney Sucked In 200: Gilpin was just a bottom-tier organiser, an ex-garbo.