Collective agreements under Dutch law are based on contract law. Under the Contracts Act in general, social partners, i.e. employers and trade unions, have the freedom to negotiate or not. This means that Dutch law does not contain a general obligation to make commitments, to conclude agreements and/or to amend them regularly, as some other countries do (for example. B la France). As collective bargaining is widely accepted in the industry, most employers will be willing to negotiate. If this is not the case, trade union action may exert pressure, but no employer may be forced by law to enter into negotiations. However, once negotiations have begun, the freedom to choose who to negotiate with, by law, even marginally. There are few specific conditions in Dutch legislation that contracting parties must meet.
Any union can enter into negotiations and become a party to the collective agreement, the only condition being that the union be a full-name association which, in its constitution, has been given the power to negotiate collective agreements.  A union shall not be elected by the staff it purports to represent and should not be subject to a review of its representativeness. This could create tensions, especially if employers decide to negotiate with smaller (or even yellow) unions, thus excluding large national unions linked to either the FNV or the CNV. Or, conversely, to negotiate with an FNV or CNV union that has little support in the enterprise, to the detriment of a more specialized and representative union. This tactic of selecting and selecting the contractor is particularly interesting in the Dutch system, since collective agreements concern all workers of employers who are bound by the agreement and not just workers who are members of a union that is a party to the agreement.  Such an agreement may, in the end, even engage the entire sector by generalizing it (see below). A striking example of this effect was given in January 2002, when child care employers entered into a collective agreement with a union against the objections of two other unions involved in the negotiations. The union that concluded the agreement had 85 (!) members among the 35,000 employees in this sector; the two opposing unions 11,500 members. Nevertheless, the unions felt that the Minister of Social Affairs could declare the collective agreement binding on the whole sector.