The formation of Mutual Aid Committees (MACs) is an integral part of the Home Affairs Department's effort to promote public participation in community affairs. A MAC is a voluntary body formed by the residents of a building.

MACs were promoted initially in private multi-storey buildings, they quickly extended to public housing estates, industrial buildings, temporary housing and squatter areas. By December 31, 2009, there were 2 714 MACs throughout the territory.

The primary aims of a MAC are to promote a sense of friendliness, mutual help and responsibility among members, and to promote better security, a better environment and, generally, more effective management within the building. These committees provide a channel of two-way communication between Government and the residents on matters affecting the well-being of the individual and the community and also provide a focal point for residents to participate in community activities.

Resident's participation is crucial to the formation and running of a MAC. In order to give general guidance to MACs in conducting their business, two sets of Model Rules have been prepared by the Home Affairs Department: Model Rules for a MAC in a Public Housing Estate and Model Rules for a MAC in a Private Building. They are obtainable at the Public Enquiry Service Centres of the District Offices.