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). When the UK introduced the nickel-brass twelve sided threepenny bit, New Zealand continued to use the smaller silver coin until decimalisation in 1967.
The specifications for the coin were (in measurement units of the time):
Diameter of Coin: 0.642 inches
Standard Weight: 21.81818 grains
Remedy Allowance (margin of error in weight): 0.212 grains
The composition of the metal was:
1933-1946: 50% silver, 40% copper, 5% nickel and 5% zinc
1947-1965: 75% copper and 25% nickel.
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 129,207,364 (129 mln).
Counting the (few) known proof mintages, the total mintage adds up to 129,232,634 (138 mln).
Of them, 43,400,604 (43 mln) were silver and 85,832,030 (86 mln) were cupronickel.
Effigy of the monarch, legend.
During the existence of the denomination, ruling monarchs for whom threepence coins 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.
Two carved patu (Maori weapons) crossed with lanyards or throngs attached, between their blades, the value and denomination 3d (abbreviation for "three pence"); above, NEW ZEALAND; below, the date.
The artist's initials KG (Kruger Gray) were omitted from the reverse of the threepence until the 1937 issue when they were placed below the centre of the crossed weapons.