The Constitution contains no rules on the formation of a Cabinet. It only deals with the beginning and the end of the formation process, i.e. the resignation of the old Cabinet and the appointment of the new Cabinet by the Head of State. The formation process is largely based on unwritten constitutional and customary law.
Rules of Procedure
On 27 March 2012 the House adopted a change of the rules governing the formation process, laid down in its Rules of Procedure. The aim of the amendment was to enable the House of Representatives to take the initiative in the formation of a new Cabinet. Before the House decided to amend its Rules of Procedure, the Head of State played a key role in the formation process. It is now laid down in the Rules of Procedure that no later than one week after the installation of a newly elected House of Representatives the House shall have a plenary debate on the election result. The aim of the debate is to draft an information assignment and to designate one or more “informateurs” to carry out this assignment. The House may also decide to skip the information stage and to start the formation process immediately. In that case the aim of the debate is to designate one or more “formateurs” and to draft a formation assignment.
The duration of the Cabinet formation
In the Netherlands, the formation a Cabinet can be a very prolonged process. This may be problematic, because in principle the outgoing Cabinet only deals with current, non-controversial affairs. A Cabinet becomes "outgoing" once the Prime Minister has tendered its resignation to the Head of State. Since 1946 the average duration of a Cabinet formation has been 89.5 days. The shortest formation, that of the Drees I Cabinet in 1948, took ten days. The longest formation took 208 days and resulted in the Van Agt I Cabinet in 1977. The formation of the current Rutte II Cabinet was completed in 52 days.