Green’s Dictionary of Slang

(Aus.) a thief’s or confidence trickster’s female associate.

1902		Truth (Sydney) 20 July 8/1: Witness said, ‘I am not speaking to you.’ Defendant replied, ‘Who are you? You’re only A CHINAMAN'S WOP.’ [...] Witness said, ‘You would not dare to call me those names here.’ He replied, ‘Go and sell the fowls you shook, you old Chinaman’s wop’ .
1913		Truth (Sydney) 9 Nov. 10: [cartoon caption] The Book, the Wop and the Mug [...] I’me [sic] here on too, the fancy ’wop’, / Of Ikey with the Bag.