Sources of employment law are the Constitution of the Federal Republic of Nigeria 1999, the Labour Act Chapter L1, federal laws enacted by the National Assembly and State laws enacted by the House of Assembly. 

There are two broad categories of employees in Nigeria. ‘Workers’ defined under the Labour Act as “who are generally employees who perform manual labour or clerical work” and ‘Non-Workers’ - employees who perform administrative, executive, technical or professional functions. The Labour Act which prescribes the minimum terms and conditions of employment applies only to ‘Workers’.  

Section 7 of the Labour Act requires every employer to issue a written contract to an employee within 3 months of the commencement of the employment relationship. The Labour act prescribes minimum terms and conditions of employment that employers must comply with including safety, sick and maternity leave, discrimination, termination and dismissals. Full detail of the act can be viewed at:  http://www.nigeria-law.org/LabourAct.htm 

There are many unions in Nigeria and they wield some power. The Nigeria Labour Congress (NLC) is an umbrella organisation for trade unions in Nigeria, it has 29 affiliated unions. In total, it has around four million members, according to its own figures, making the association one of the largest trade unions in Africa. In the past they have instituted national strikes for worker rights. 

The official current (May 2019) minimum wage is N30,000/month ($ 83.00/month). 

Unskilled manual labour is plentiful and relatively cheap and when there are no time considerations, often used to as an option rather than expending capital on machinery.