The Dutch government has been barred from stripping a man who was jailed for joining a terrorist group of his passport after a judge ruled it breached the UN treaty on racial discrimination.

The 38-year-old, who has dual Dutch and Moroccan nationality, spent five years and four months in prison after he travelled to Syria and joined the militia groups Ahrar al-Sham and Jund al-Aqsa.

Junior justice minister Ingrid Coenradie wanted to revoke the man’s Dutch passport and ban him from entering the Netherlands for 20 years, but a judge in Amsterdam ruled that the move was unlawful because it discriminated against dual nationals.

The court ruled that the move violated the United Nations Convention on the Elimination of All Forms of Racial Discrimination (ICERD), which the Netherlands is a signatory to. “The junior minister is making a distinction based on a person’s origin,” the judge wrote.

Justice minister David van Weel said the government would appeal against the decision.

“We are not pursuing this policy for no reason,” he told parliament on Tuesday. “Criminals who have been convicted for terrorism don’t deserve Dutch nationality and should leave as soon as possible.”

The man was convicted in 2019 for travelling to Syria and joining the two organisations. The Jihadist rebel group Ahrar Al-Sham has not been sanctioned by western governments, but the court in Rotterdam ruled that it was a terrorist group that pursued “sectarian hatred”. Jund al-Aqsa has been designated as a terrorist organisation by the United States and other countries.

The current Dutch government is committed to limiting dual nationality as far as possible, but is constrained by international treaties.

Geert Wilders, leader of the far-right PVV, last year withdrew a draft law that would have barred dual nationals from voting or holding public office as one of the conditions for forming a coalition with the VVD, NSC and BBB parties.