Thirteen migrants absconded from the Initial Reception Centre in Marsa on Monday-Tuesday night, but five have since returned, the Agency for the welfare of asylum seekers said on Tuesday evening.
The migrants were being held in Marsa to be assessed and for medical clearance.
Another two migrants ran away from the Office of the Refugee Commissioner when they were taken there to apply for protection, the agency said.
The police are conducting a search for the migrants who remain at large.
It is understood that the migrants were part of a group rescued by the Armed Forces of Malta last week.