An IncorporatedSociety is a legal entity that has been registered under the Incorporated Societies Act. Becoming an IncorporatedSociety allows a group or organisation to run its affairs as if it were an individual person. Any group of 15 or more people may form an IncorporatedSociety -- companies and other Incorporated Societies may be members of an IncorporatedSociety but they only count as one member.
Incorporated societies are administered through the NZ Companies Office. For more information refer to the government incorporated society website - http://www.societies.govt.nz