Asylum seekers arrive at temporary shelter at the Malmö Mässan conference centre during the migration crisis of 2015.

Lyssna: Thousands of failed asylum seekers still undetected

Sweden's police force managed to enforce only about one-third of its expulsion orders for rejected asylum seekers during the first quarter of this year, despite government demands for an improvement.

Of the nearly 3,000 failed asylum seekers who should have left the country, the police reported that more than 2,000 people had gone underground to avoid detection.

The police have told the government that one of the factors behind the failure to eject more people is that...