Green’s Dictionary of Slang

(Aus.) to victimize; to challenge aggressively.

1950		Truth (Sydney) 23 July 47/1: ‘I don’t want to pick you, as I want to live. You know, everybody knows, these ----- charity dames were doing it for love in our territory’.
1955		D. Niland Shiralee 69: The sergeant back there — he wasn’t a bad bloke. But he would have picked him all right.
1981		A. Weller Day of the Dog 39: ‘You shouldn’t fight because it doesn’t get you anywhere.’ ‘They was pickin’ my woman.’.