The series of six coins are minted in silver and gold, including one 11mm gold coin weighing half a gram, and will be released on May 3.
The coins were designed by Stephen Fuller of Wellington and, as was tradition, the King's portrait faced in the opposite direction of his mother, Queen Elizabeth II, who died in September last year, aged 96.
The design was personally approved by the King.
NZ Post stamps and collectables head Antony Harris said King Charles III would be the first king of New Zealand to appear on the country's decimal currency.
"It is fitting that the first appearance of His Majesty's effigy will be on coins commemorating the coronation."
New Zealand coins have always featured a portrait of the reigning monarch, beginning with King George V in 1933 when New Zealand coinage was first introduced to replace British currency.
NZ Post will also issue stamps to commemorate the coronation, including a sheet featuring images from the coronation ceremony on 6 May.