Police say the Arena clan made money by providing services at Isola di Capo Rizzuto in Italy's far south and siphoning off state funds.
The clan is alleged to have hidden behind a local Catholic charity which officially runs the centre.
The claims came to light on Monday, when officers arrested 68 people, including a local priest.
Another of those arrested was Leonardo Sacco, head of the Catholic Misericordia association that is supposed to control the Sant'Anna Cara immigrant centre. The centre holds 1,500 people at a time.
