Green’s Dictionary of Slang

(Aus./N.Z.) any person or thing considered notably excellent, attractive, strong etc.

1898		N.Z. Thames Star 23 July 4/3: The general here is a pure Napoleon [...] he is a regular ‘snitcher’.
1938		Press (Christchurch) 2 Apr. 18: New Zealanders have their curiously sounding slang. ‘Prejaganint’, ‘snitcher’ or ‘snozzler’ (a good specimen).
1941		Baker N.Z. Sl. 51: Of children’s terms [...] we may note snitcher, snitch, [etc.] [...] descriptive of something superlative or excellent, both as nouns and adjectives.
1955		N. Pulliam I Travelled a Lonely Land (1957) 239/1: snitch – a very worthwhile person, a top-notch or first-class thing.
1970		N. McNaughton Tat 55: So far they were delighted with her [i.e. a sheep-dog]. She was easy to command, knew her drill [...] She was a ‘snitcher.’ [DNZE].
1988		McGill Dict. of Kiwi Sl. 105/2: snitcher attractive person or thing, c.1935.
2003		McGill Reed Dict. of N.Z. Sl. [as cit. 1988].