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 commemorative, bullion and collector coins under the authority of Niue. These coins are dedicated to historical or general popular culture themes not related to Niue itself. Many of them are made using "smartminting" techniques and have features not generally found in circulation coins - e.g. high relief, full colour printing and/or different forms, including fully three dimensional (3D).
Some coins are marketed in standard bullion sizes, like half ounce silver, one ounce silver etc, and some of those are also denominated as $1, for which see separate lists; listed below are coins denominated as One Niue Dollar which are not in a standard ounce-based size. The coins are distributed at prices much higher than the value of the precious metal they contain, and are targeted at collectors who appreciate them for their artistic or rarity value.
Note that the various mints have been authorised to use different effigies of the monarch (who, strictly speaking, is monarch of New Zealand and not of Niue), so the obverses are inconsistent. | 
