Green’s Dictionary of Slang

1. (Aus.) using blacks and whites as fellow-workers.

1905

Bulletin (Sydney) 10 Aug. 18: Thing first is leaving the country because Australia isn’t piebald & won’t let him employ black slavery on his sugar plantation.

2. (Aus.) half-caste, mixed-race.

1905		Bulletin (Sydney) 17 Aug. 13/1: For some years a white barber has battled along [...], displaying a placard to the effect that his business has no connection with the adjoining shops of Chows, Bashi-Bazouks, etc., who gradually ousted his white neighbors. Passed the place recently, and noticed that the piebald alien had at last slopped over into the barber’s shop.
1910		Bulletin (Sydney) 22 Sept. 11/4: By the way, the binghies in this district all more or less speak Malay, and blacks and Malays are intermarried (another piebald-Australian problem).
1961		(con. early 1950s) J. Peacock Valhalla 347: Butch and the piebald Negro looked on anxiously.