Niue, a sovereign state in free association with New Zealand, uses two official legal tender currencies. The New Zealand Dollar is the circulation currency for daily transactions, while the government also authorises legal tender coins in the Niue Dollar currency for collector's purposes.
A number of mints issue a large variety of coins under the authority of Niue. Most of these are commemorative and collector issues dedicated to historical or general popular culture themes not related to Niue itself. Others are bullion coins in sizes based on the troy ounce, or metric - including the extremely large one kilogram of gold format (abbreviated as 1 kg Au, where "Au" comes from the Latin word for gold, Aurum). These gold coins are targeted at bullion investors and are released at prices close to the intrinsic value of their precious metal content.