The organization, the 'Ndrangheta mafia, also illegally supplied concrete for the A3 motorway expansion from Salerno to Reggio Calabria, one of Italy's largest infrastructure projects and one that has been behind schedule for years, the ANSA news agency reported.
"This is the way to do it, to fight organized crime every day," said Interior Minister Roberto Maroni.
Police said profits generated from bilking the motorway project touched off a turf war that led to dozens of killings in the 1980s and 1990s.
Three unidentified members of the tax police were arrested for allegedly alerting another 'Ndrangheta clan to tax inspections that were scheduled for front companies, ANSA said.
Notable deaths of 2014 [PHOTOS]
Ebola cases top 10,000, WHO report says