There are two types of detention of asylum seekers. Either a person is detained at the external border, trying to access the Schengen area in the Netherlands (border detention), or they can be detained in case they are undocumented and subjected to a return decision (territorial detention).
Statistics published by the Ministry of Justice and Security do not distinguish asylum seekers from other categories of persons in immigration detention:
|Immigration detention in the Netherlands
Source: Repatriation and Departure Service, Inflow and departure figures, available in Dutch at: https://bit.ly/3CuZi6Y.
Border detention: Pursuant to Article 6(1) and (2) of the Aliens Act, the third-country national who has been refused entry when he or she wants to enter the Schengen area at the Dutch border, is obliged “to stay in a by the border control officer designated area or place, which can be protected against unauthorised departure.” 
If an asylum seeker makes an asylum application at an external border of the Netherlands, his or her application will be assessed in the Border Procedure. Consequently, these asylum seekers can be detained based on Article 6(3) of the Aliens Act.
There is one border detention centre for detaining asylum seekers. Asylum seekers who enter the Netherlands via airplane or boat are required to apply for asylum at the detention centre at Justitieel Complex Schiphol. During this procedure, the asylum seeker will be placed in detention and the whole asylum procedure will take place in detention. Both of the personal interviews (eerste gehoor -first interview and nader gehoor-second interview) take place in the detention centre. The Dutch Council for Refugees will prepare the asylum seekers for these interviews; moreover, a staff member of the Dutch Council for Refugees can be present at the personal interview. This depends on whether the asylum seeker requests this and whether there is enough staff available. The lawyer is also allowed to be present at the hearing but in practice, this rarely happens, as lawyers do not receive a remuneration for this activity. During the interview, there are IND accredited interpreters present. Following the Gnandi judgement of the CJEU, the grounds for detention during the appeal procedure have been altered in the Aliens Act, see Border Procedure.
Territorial detention: Asylum seekers may also be detained in the course of the asylum procedure on the territory, in accordance with Article 59b of the Aliens Act, which transposes Article 8 of the recast Reception Conditions Directive. Article 59a of the Aliens Act foresees the possibility to detain an asylum seeker for the purpose of transferring him or her under the Dublin Regulation. This article refers to Article 28 of the EU Dublin Regulation.
Territorial detention is also applicable to persons without a right to legal residence under Article 59 of the Aliens Act. Detention based on Article 59 cannot be applied to asylum seekers during their asylum procedure or in some cases – after the Gnandi judgment – while they are waiting for the result of their appeal.
 Article 6 Aliens Act.
 Article 6a Aliens Act.
 Regional Court Haarlem, Decision NL18.16477, 19 September 2018; Decision NL18.19950, 6 November 2018.
 CJEU, Case C-181/16 Sadikou Gnandi v Belgium, Judgment of 19 June 2018.
 Secretary of State of Justice and Security: Memorie van antwoord Wet terugkeer en vreemdelingenbewaring, 13 December 2018, available in Dutch at: https://bit.ly/2I580Po, 7. There was also a decision from the Regional Court of the Hague, Decision NL18.11194, 26 June 2018, with the same conclusion.