Green’s Dictionary of Slang

1. (orig. Aus.) a pneumatic drill [like the SE kangaroo, it ‘jumps up and down’].

1975

Sun-Herald (Sydney) 20 July 13/2: Her friend [...] prefers a bone-shaking ride on a ‘kanga’ — a jack-hammer, to the uninitiated.

2. (Aus.) a white child [the TV series Skippy, the Bush Kangaroo].

1987

Times on Sun. (Aus.) 22 Nov. 25: Children tend to use their own ethnic language in the playground. The Anglos, also known as ‘Kangas’ or ‘skippies’, are often infuriated by this [GAW4].