Citizens of the European Union are welcome to stay in the Netherlands , however they are required to validate the purpose of their stay.

After a free period of the first 6 months after arrival to the Netherlands, the EU nationals should be able to confirm that he or she have a purpose to stay in The Netherlands, either as an employee, a student, a service provider, an entrepreneur or as a family member of a legally residing person. EU citizen who wishes to stay for  a longer period than six months, he/she are required to register at the Immigration Office.(IND)

EU citizens from Bulgaria and Romania do not have yet a free access to the Dutch labour market.
All other EU citizens have unrestricted access to the Dutch labour market.