As a general rule, you must obtain a permit to work in Denmark even though your job is voluntary and without pay.

However, certain groups of so-called third-country citizens are exempt from the work permit requirement because of their profession or special situation. 

You can read more about the rules of exemption here.

If your job requires a work permit but is unpaid:

You can apply for a residence permit as a volunteer if you are between 18 and 30 years of age, and you will be doing voluntary, unpaid work of a social or humanitarian character in Denmark.

You can read more about a permit as a volunteer here.

You can also apply for a residence permit as an intern if you will be doing an unpaid internship in Denmark as a part of your education in your home country.

You can read more about a permit as an intern here.

As an au pair in Denmark, you have, in addition to your residence permit as an au pair, already been permitted to take voluntary, unpaid work for an organisation or an association. The work should be of benefit to persons that neither you, nor your host family is related to.

You can read more about a permit as an au pair here.

If you are granted a residence permit allowing you to work for a specific employer, as self-employed or as Ph.D student, the permit also allows you to carry out unpaid, voluntary work.

This means that you do not need to apply for a specific permit if you, besides your main employment would like to work as an unpaid volunteer for example in an association, a public institution, at a cultural event, as a volunteer visitor, in your child’s kindergarten or school or the like.

Please note that it is a precondition that the job in question is normally carried out unpaid and voluntarily. Your unpaid voluntary work is not allowed to replace paid workforce.

Please find further information on residence permit for work here.