Italian police say they have confiscated mafia assets $1.7 billion - the biggest seizure of its kind in history.

The multi billion-dollar haul included the seizure of 43 wind and solar energy companies, 98 properties and 66 bank accounts belonging to Vito Nicastri, a businessman described by authorities as a frontman for the Sicilian Mafia.

Nicastri, 57, was once dubbed 'Lord of the Wind' for his holdings in wind farms which prosecutors say were funded by extortion, drug sales and other illicit activities.

Three years ago, investigators found the mafia was engaged in a massive eco-scam, claiming generous grants for investment in wind-power and environmentally- friendly businesses.

"This is a sector in which money can easily be laundered," Arturo de Felice, head of Italy's anti-mafia agency, told local media.

"Operating in a grey area helped him build up his business over the years."

The anti-mafia agency in a statement said it was the biggest seizure of mafia-linked assets.

The assets had been frozen in 2010 and Nicastri is on probation under orders not to leave his home town of Alcamo in western Sicily during the investigation.

Nicastri had "numerous and high-level contacts with mafia figures", the anti-mafia agency said, adding that this had been confirmed by messages found during the arrest of two local mafia bosses.

The businessman was also linked to Matteo Messina Denaro, a fugitive who is considered the godfather of the Sicilian mafia, the statement said.

The seizure "impacts in a significant way on the economic power of Matteo Messina Denaro, who is considered the lord of that land," it said.

Mr De Felice said the seizure "will definitely make life more difficult" for Messina Denaro.

He said revenue from the companies and properties seized would now be going to the state.

ABC/AFP