Initially, British and Australian coins circulated in New Zealand. The devaluation of the New Zealand pound relative to sterling in the 1930s led to the issue of distinct New Zealand coins in 1933, in denominations of 3d, 6d, 1s, 2s (the florin) and 2½s (the half-crown), minted in 50% silver until 1946 and in cupro-nickel from 1947. In 1940, bronze ½d and 1d coins were introduced. All these denominations were the same size and weight as their equivalents in the Australian and UK coinage (although Australia never minted the half-crown).
According to Encyclopaedia of New Zealand 1966, the original specifications for the coin were (in measurement units of the time):
Diameter of Coin: 1.272 inches
Standard Weight: 218.18181 grains
Remedy Allowance (margin of error in weight): 1.216 grains
In regards to statistics, it has to be noted that the mintage figures provided by the Reserve Bank of New Zealand include, in some cases (like the 1953 mintages), the proof issue of the year while in most other cases they do not.
According to the Reserve Bank of New Zealand, the total mintage of the denomination during its existence was 21,808,164 (22 mln).
Counting the (few) known proof mintages, the total mintage adds up to 21,833,434 (22 mln).
Of them, 9,801,404 (10 mln) were silver and 12,032,030 (12 mln) were cupronickel.
Effigy of the monarch, legend.
During the existence of the denomination, ruling monarchs for whom half crowns were minted were King George V, King George VI and Queen Elizabeth II. No coins were minted for King Edward VIII during his short reign.
After the Independence of India in 1947, the title "Emperor" was dropped from the legend of King George VI.
Shield of Arms of the Dominion of New Zealand on their shield (quartered with the Southern Cross, a wheat sheaf, a lamb suspended by a ribbon and mining hammers crossed divided by three ships) surmounted by the Royal Crown and surrounded by ornamentation inspired by Maori carvings; around, NEW ZEALAND HALF CROWN; below, the date; in small letters to right of date the artist's initials K.G. ([George] Kruger Gray).