Green’s Dictionary of Slang

(N.Z. camp gay) a police officer, usu. male.

2003		K. Cage Gayle.
2010		(con. 1960s) W. Ings ‘Trolling the Beat to Working the Soob’ in Int’l Jrnl Lexicog. 23:1 72: In the early 1960s in New Zealand Vivian Vice, Nelly-law, Dolly Handbag, Alice, Dora-D, Hilda-Handcuff, Lily-lunchbox, Jennifer-Justice, Hilda Box-rot, Petunia Pig, Tilly Tight-twat, and Cherie Cunstable, were familiar.
2019		P. Baker Fabulosa 293/2: Jennifer Justice the police.