The purpose, role, status, powers and functions for local authorities generally are set out in the Local Government Act [1].
The purpose of local government is to enable democratic local decision-making and action by, and on behalf of, communities.
The role of a local authority is to:
give effect, in relation to its district or region, to the purpose of local government; and
perform the duties, and exercise the rights, conferred on it by or under the Local Government Act (and any other enactment).
Status
A local authority is a corporate body which continues to exist despite changes in membership [2]. As a legal entity it can hold property and enter contracts in its own name; it is separate to any of the individuals that comprise the elected governors or management.
Powers
Any council that is a territorial authority must exercise its powers under this section wholly or principally for the benefit of its district.
Any council that is a regional council must exercise its powers under this section wholly or principally for the benefit of all or a significant part of its region, and not for the benefit of a single district.
As a unitary authority. Auckland Council is both a regional and district council.