In 1983 the main ministry staff consisted of about 5,300 persons; the Immigration Department employed about 2,900, the Fire Service Department 900, and the Nigerian Prisons Service 23,000. In August 1988, the authority to arrest and detain suspects without trial, formerly assigned to the chief of General Staff and to the inspector general of police, was extended to the Ministry of Internal Affairs.
The ministry also had a paramilitary Security and Civil Defence Force, whose size, mission, and organization were unknown. In August 1989, it was announced that this unit was to be reorganized. Nigeria had a dual prison system for more than a half century until the consolidation of the federal and local prisons in 1968. The Nigerian Prison Service, a department of the Ministry of Internal Affairs, was headquartered in Lagos and headed by a director responsible for administering nearly 400 facilities, including regular prisons, special penal institutions, and lockups. All of these facilities since 1975 came under federal control. Nigeria's prison system, as in most Third World countries, is grossly inadequate. Most prisons have no toilet facilities, and cells lack water. Mistreatment of inmates is common, abuse frequent, and torture occasional.