Police say they have arrested a businessman on charges of extorting money from Premier Silvio Berlusconi in return for his cooperation in a probe over recruiting prostitutes to attend wild parties at Berlusconi's home.

Police arrested Giampaolo Tarantini and his wife in Rome Thursday, police in Naples said.

Tarantini has admitted he paid a high-end prostitute, Patrizia D'Addario, and other women to attend parties at Berlusconi's residences, but insists the premier didn't know.

Naples Prosecutor Francesco Greco said Tarantini had compelled Berlusconi to pay his family legal and housing costs in exchange for Tarantino's cooperation in the prostitution investigation.

Berlusconi says he wasn't victimized by Tarantini and says he was just helping a needy family.