The operation in Caserta, north of Naples, targetted the Iovine clan, believed to be one of the most powerful groups in the Camorra, police said in a statement.
Giuseppe Iovine, brother of fugitive clan leader Antonio Iovine, was among those arrested, police said.
They are accused of extortion, illegal arms possession and money laundering, the statement said.
"The clan has been involved in systematic bribing of civil servants to win public tenders and swayed local elections in 2004 in favour of the candidates they liked," the statement said.
The seized assets had been laundered and invested mainly in real estate and listed companies, they said.
The crackdown also netted weapons including shotguns and an assault rifle (AK-47), as well as ammunition, the statement said.