Essential services may refer to a class of occupations that have been legislated by a government to have special restrictions in regard to labour actions, such as not being allowed to legally strike.
The International Labour Office, a United Nations agency, makes distinctions between an essential service and a minimum service.
582. What is meant by essential services in the strict sense of the term depends to a large extent on the particular circumstances prevailing in a country. Moreover, this concept is not absolute, in the sense that a non-essential service may become essential if a strike lasts beyond a certain time or extends beyond a certain scope, thus endangering the life, personal safety or health of the whole or part of the population. 585. The following may be considered to be essential services:While maintaining a right to strike, the ILO recognizes situations and conditions under which a minimum operational service could be required.
606. The establishment of minimum services in the case of strike action should only be possible in: (1) services the interruption of which would endanger the life, personal safety or health of the whole or part of the population (essential services in the strict sense of the term); (2) services which are not essential in the strict sense of the term but where the extent and duration of a strike might be such as to result in an acute national crisis endangering the normal living conditions of the population; and (3) in public services of fundamental importance.Examples where the ILO considered conditions met for a minimum operational service include a ferry service, ports, underground railway, transportation of passengers and commercial goods, postal services, refuse collection service, the mint, banking services, petroleum sector services, education services, and animal health services.