Forty-five persons are being held in detention after they were found to be staying or working in Malta illegally, the police said.
Twenty were arrested during raids in Qormi and Marsa on Saturday while the rest were held after raids in Paceville and St Julian's earlier in the week.
The migrants are from Nigeria, Ghana, Syria, Gambia, Sri Lanka, Bangladesh, Togo, Turkey and India.
Arrangements are being made for their repatriation.