Green’s Dictionary of Slang

(N.Z./US) a sandwich.

1965		(con. 1930s) R. Wright Lawd Today 103: ‘Five sammies ’n’ four malts!’ the girl yelled aside out of the corner of her mouth.
1986		C. Bowles G’DAY 27: LES: Wossfer tea? [...] MAUREEN: Spag bog [...] You doan like it, there’s Vegemite inner cupboard. Make yerself a sammie.
2003		McGill Reed Dict. of N.Z. Sl.