About the Design:

Obverse
Fourth crowned portrait of HM Queen Elizabeth II facing right, wearing the Girls of Great Britain and Ireland Tiara, legend around, date below.

Lettering:
NEW ZEALAND ELIZABETH II
IRB
Year

Reverse
A Tuatara (Sphenodon punctatus), denomination. The Tuatara is an endangered, lizard-like reptile endemic to New Zealand.

Lettering:
5
JB

Composition    Copper-nickel
Weight            2.83 g
Diameter    19.43 mm
Thickness    1.3 mm
Shape            Round