General Powers
General
Local authority powers are prescribed by law. The functions of local authorities derive from statute. Their authority and ability to spend monies are limited to  those laid down by law.
They do not have power to act outside of the functions and authorities conferred by law. Similar principles apply to private companies, but they have been heavily modified.
In order to act in relation to particular matter, the local authority must have power conferred by law. Local authorities are conferred with numerous separate powers under schemes of legislation. In recent times legislation has given local authorities more general powers to represent their community. The principle of limited authority, however, still exists.
Challenge to Powers
Actions and transactions by local authorities outside of their powers may be held void by the courts. They are said to be ultra vires, the Latin for outside of powers.
Challenges to local government action  may be based on lack of the requisite powers. This has commonly arisen in relation to contentious matters such as planning permissions, compulsory acquisition, et cetera.
In accordance with general principles, the courts imply that local authorities have incidental powers to do things which are incidental to and consequential on the functions conferred by law.
General Power Granted
Significant reform of the older rule was undertaken in the Local Government Act 1991. This was restated in the 2001 consolidating act.
A local authority is empowered to do anything ancillary, supplemental or incidental or consequential or unnecessary to give full effect or  which will facilitate or is conducive to the performance of a function conferred by the Local Government Acts (or any other enactment) or which  can advantageously be performed by the authority in conjunction with the performance of such function.
It is provided that a local authority may not however, perform any function which is prohibited from performing under legislation or performing a function without compliance with necessary condition or restriction which applies to that function.
Local authorities may take such measures, engage in activities or do such things in accordance with law including expenditure as it considers necessary or desirable to promote the interest of local communities.
For this purpose a measure, activity or thing is deemed to promote the interest of the community if it promotes, directly or indirectly, social inclusion or the social economic, environmental, recreational, cultural community or general development of the local authority area or part of it or of the local community or group consisting of members of it.
Works
Without limiting the above, a local authority may
- carry out work and maintain works on land. Provide managers are preserved, structures of any or facilities
- fit out furnish and equip building, structures or facilities for particular purposes
- provide utilities, equipment for purposes.
- provide any service or engage in any activity that, in the opinion of the council is likely to be beneficial to the local community
on such terms as it considers appropriate.
Assistance
They may  provide
- assistance in money or in kind including
- prizes and incentives in respect of organisation or promotion of competition,
- seminars, exhibition, displays,and
- other events or organise and promote such events
on such terms it considers appropriate
They may
- provide assistance in money or in kind to persons engaged in activities that is in the opinion of the council, beneficial to the community in the area
- enter into contracts or make arrangements as it sees fit either alone or jointly with other local authorities or public authorities
Factors to be Considered
A local authority in performing its functions must have regard to
- its resources from whatever source that are available or likely to be available for the purpose of such performance and the need to secure the most beneficial, efficient and effective use of such resources
- the need to maintain services adequately provided by it as are considered essential and insofar as practicable to ensure a reasonable balance is achieved taking account of all factors in its function or program
- the need for cooperation and coordination of its activities through the local and public authorities and governmental bodies in relation to performance of  particular functions
- the need for consultation with other local and public authorities in appropriate cases
- the new policies and objectives of the government or Minister as they may affect the area or function concerned
- the need for a high standard of environmental and heritage protection and the need to promote sustainable development.
- the need to promote social inclusion
The above provisions do not limit the local authority’s obligations to provide the functions designated by law which it must provide. However, every provision of law is subject to the above general provision.
1991 Act
The 1991 Local Government Act sought to reduce the significance of this principle by giving local authorities general competence to promote the interest of the community as they consider appropriate.A broad range of measures are deemed to promote the interest of the community.
Local authorities
- may carry out works,
- provide and maintain lands, structures or facilities, furniture fit-out and buildings,
- provide equipment, material, utilities,
- provide services that benefit the local authority,
- provide assistance in money or enter contracts
- as they consider necessary.
The general power may not be used to perform a function wholly outside that conferred on local authorities.
A local authority may accept gifts of land, money and property.  The gifts must not be inconsistent with the effective performance of the functions of the authority. Details must be published in the annual report. A local authority may enter into contracts and engage consultants as may be required for its functions.