The law provides for a maximum of a 2-month detention period for asylum seekers. Detention can be prolonged for another 2 months for reasons of national security or public order. Where extended for these reasons, a one-month prolongation if possible each time. The maximum duration of detention on territory therefore cannot exceed 6 months (2+2+1+1). The detention at the border may not exceed 5 months. However, the period of detention is suspended for the time provided to appeal the decision on the asylum application.
Since the entry into force of the law in 2018, asylum seekers in the Dublin procedure may be detained in order to determine the responsible Member State and in order to secure a transfer. In both cases detention may not exceed 6 weeks.
On 19 July 2019, Article 51/5/1 of the Aliens Act entered into force and implements the relevant articles on detention of the Dublin III Regulation for applicants who did not apply for asylum in Belgium, but who could be subject to a take-back decision because of a previous application that was registered in another Member State.
Contrary to the Dublin III Regulation, the law does not mention that the detention should be as short as possible. Furthermore, when a transfer decision is being appealed through an extremely urgent necessity procedure, the detention period starts again. This means that a new period of six weeks will start after the rejection of the appeal in the extremely urgent necessity procedure.
When detained at the border, asylum seekers generally spent more time in detention then other migrants in detention. Since 2018, asylum seekers are admitted to the territory if the CGRS has not taken a decision within four weeks, or when the CGRS decides that further investigation is necessary. However, being admitted to the territory does not automatically mean that the asylum seeker will be set free. As shown in practice, the Immigration Office can take a new detention decision based on one of the grounds set out in article 74/6(1), which regulates detention on the territory.
While the duration of detention of asylum seekers is unknown in practice, the Immigration Office stated that the average duration of detention of all persons detained in immigration detention was 42 hours in 2020.
 Articles 74/5 and 74/6 Aliens Act.
 Before this legal amendment, these decisions could not be delegated by the minister to a staff member of the Immigration Office.
 Article 74/5(4)(4) and (5) Aliens Act, as amended by the Law of 21 November 2017.
 In 2017 this was 34,6 days; see: Myria, ‘Myriadoc 8: Retour, détention et éloignement’, December 2018, available in French at: https://bit.ly/2FPAo6t, 10.