A major function of the development plan system is to ensure an adequate and continuous supply of housing land. Zoning of housing land will be carried out in close consultation with elected representatives, local communities and the various public, voluntary and private agencies responsible for housing provision.

The majority of Northern Ireland's population lives in settlements and it is there that much of the demand for new housing and associated facilities and services will be met. The potential of each settlement to accommodate housing needs will be assessed and each settlement's future development planned.

Environmental impact will be balanced with the need to make land available in locations attractive to developers and to provide an acceptable choice of sites m settlements. It is desirable that housing developments are closely related to centres of employment to avoid problems of labour or housing shortage or inefficient transport costs due to unnecessary commuting.

The extent of zoning, appropriate to a particular settlement, will normally reflect expected future needs and will be judged against regional policies, environmental criteria, the existing infrastructure capacity of the settlement, and the need to conserve land and natural resources and protect the natural and man-made heritage. Account will be taken of demographic and economic developments in each area, changing patterns of employment and travel to work, and trends in market demand for housing. Of increasing concern, because of the changes in society, are the special housing requirements of people in need of help or supervision, who may have particular locational requirements and for whom conventional housing may not be suitable.

Development plans will normally identify infrastructure or other constraints to the development of zoned sites. Development control advice in the form of a development brief may also be produced for specific development sites.