Constitutional Court, 17 April 2006, Case No. 4635-2004-AA/TC

Constitution of Peru

Article 3

The list of rights set out in this chapter does not exclude any others guaranteed by the Constitution, those of an analogous nature or based on the dignity of man, the principles of the sovereignty of the people, the democratic State of law and the republican form of government.

Article 55

Treaties ratified by Peru and in force form part of domestic law.

Article 56

Treaties must be adopted by Congress before their ratification by the President of the Republic, whenever they deal with the following subjects: 1. Human rights; 2. The nation’s sovereignty, dominion or territorial integrity; 3. National defence; 4. Financial obligations of the Government.

Article 57, paragraph 2

Whenever a treaty affects constitutional provisions, it must be approved through the same procedure governing constitutional reform before being ratified by the President of the Republic.

Final transitional provision No. 4

Provisions concerning the rights and freedoms recognized by the Constitution are interpreted in accordance with the Universal Declaration of Human Rights and with treaties and international agreements dealing with the same issues and ratified by Peru.

Labour Procedure Law (No. 29497 of 2010)

Supplementary provision n°10

In accordance with the provisions of the fourth final and transitional provision of the Political Constitution of Peru, individual and collective labour rights shall be interpreted in accordance with the Universal Declaration of Human Rights and the relevant international treaties and agreements ratified by Peru, in addition to the consultation of the pronouncements of the supervisory  bodies of the International Labour Organization (ILO) and the opinions or decisions adopted by international courts constituted according to treaties to which Peru is party.

Hours of work , Occupational safety and health
Role of International Law:
Use of international law as a guide for interpreting domestic law
Type of instruments used:

Ratified treaties;1 Instruments not subject to ratification;2 Work of international supervisory bodies



Mining company/ Work day of 12 hours and 48 hours per week/ Settling the constitutional character or not of that arrangement of hours worked/ Principle of the most favourable provision/ Links between hours of work, health and safety and human dignity/ Use of international law as a guide for interpreting domestic law



Two union representatives of a mining group asked for a court order to obtain implementation of their company’s collective agreement providing for an eight-hour working day for miners and putting an end to a so-called “4x3” system consisting of four days of work of 12 hours each followed by three days of rest. Not having won their case before the ordinary courts, the union representatives referred the matter to the Constitutional Court, claiming violation of the maximum length of work stipulated in the Constitution of Peru,3 an affront to human dignity and violation of the principle of equality.



The employer indicated that the organization of working hours set by the mining company was in agreement with the Constitution of Peru by not exceeding the 48 hours weekly mentioned in Article 25 of the Constitution. The defendant stressed that the Constitutional Court had already declared that type of arrangement of working hours constitutional in previous decisions. The defendant also pointed out that the schedules applied by the company were in accordance with the legislation governing mining activities and that the company’s collective agreement allowed the employer to change working hours under certain circumstances.



Before beginning to study the dispute, the Court referred to a report of the International Labour Office on working conditions and health and safety in the mining sector in Peru.4  The Court referred to that report to point out that work in the mines was considered to be a high-risk activity requiring special protection measures, specifically because of the very strenuous physical efforts required by workers and the many occupational illnesses to which the latter are exposed.



The Court then took up the question of the conformity of the “4x3” system with Article 25 of the Constitution concerning hours of work. The Court pointed out that because of the Constitution’s final transitory provision No. 4, that article should be interpreted in the light of the Universal Declaration of Human Rights and treaties ratified by Peru dealing with that question. In addition to the Declaration mentioned above,5 the Court considered the following instruments to be pertinent: ILO Convention No. 1 on Hours of Work (Industry),6 the International Covenant on Economic, Social and Cultural Rights7 and the Additional Protocol to the American Convention on Human Rights covering economic, social and cultural rights.8



In order to determine the sense and scope of the constitutional provision limiting hours of work, the Court sought to apply those various international sources in an integrated manner, following the principle of the most favourable provision.



The Court looked at the various pertinent provisions and their most protective aspects and stated that:



(a) Working eight hours per day and 48 hours weekly are defined as the maximum period. (b) It is possible to work more than eight hours per day and 48 hours per week under certain circumstances, provided that the average number of hours worked, calculated for a period of three weeks or for a shorter period, does not exceed eight hours per day or 48 hours per week. That possibility will depend on the type of work carried out. (c) The working day shall respect reasonable limits. (d) Hours of work shall be less for dangerous, unhealthy or night-time work. (e) In the case of our country, the Constitution imposes a maximum period of work of 48 hours per week. The latter was the provision providing the most protection, and it took precedence over all other provisions of the treaty imposing a greater weekly period (for example, Article 4 of ILO Convention No. 1). The Court also considered an observation of the ILO Committee of Experts on the Application of Conventions and Recommendations concerning the application by Peru of ILO Convention No. 1.9



Taking into consideration, first, the dangerous nature of the work in the mines and, secondly, the constitutional provisions concerning hours worked, as interpreted in light of international law, the Constitutional Court decided that a reasonable working day in a mine should not exceed eight hours per day, which would also ensure respect for the constitutional provisions concerning health and the principle of “decent work” promoted by the ILO. The Court declared unconstitutional not only the “4x3” system for miners but also laws concerning the mining sector making possible that arrangement of hours of work.





1 ILO Convention on the Hours of Work (Industry), 1919 (No. 1); International Covenant on Economic, Social and Cultural Rights, 1966; Additional Protocol to the American Convention on Human Rights in the Area of Economic, Social and Cultural Rights (“San Salvador Protocol”), 1988.


2 Universal Declaration of Human Rights, 1948.


3 Article 25 of the Constitution of Peru: “The normal length of a working day is a maximum of eight hours per day and 48 hours per week.  In the event that working time is accumulative or atypical, the average hours worked during that period shall not exceed that maximum.”


4 International Labour Office, Equipo Técnico Multidisciplinario para los Países Andinos: Informe sobre las Condiciones de Trabajo, Seguridad y Salud Ocupacional en la Minería del Perú (Lima, 2002).


5 Article 24 of the Constitution of Peru.


6 Articles 2, 2(c) and 4 of the Constitution of Peru.


Full text of the decision