ROME (AFP) - Police in Italy say they have cracked open a violent Chinese criminal group which had infiltrated the national transport sector and expanded into France, Germany and Spain.

Thirty-three suspects were arrested in a sting operation against a "Chinese mafia organisation" accused of using "intimidation and violence" to prey on Chinese companies looking to transport products by road, police said on Thursday (Jan 18).

As well as controlling the movement of goods throughout Italy and on to Paris, Madrid and the German city of Neuss, the gang was also lining its nest with money from "extortion, usury, illegal gambling houses, prostitution and drugs peddling", it said.

The mastermind was one Zhang Naizhong, 57, who goes by the nickname "the black man" and who behaved like a stereotypical mafia boss, dining in fine restaurants while underlings grovelled, according to the Repubblica daily.

His young lover was among those arrested by officers, who found bundles of cash stashed in her apartment, it said.

The investigation, dubbed "China Truck" and opened in 2011, was carried out by police in Prato, a city in Tuscany with a large Chinese community, working mainly in the textile industry.

The suspects hailed from the Zhejiang and Fujian eastern coastal provinces in China.

As part of the sting, police said they seized several companies, vehicles, properties and current accounts "for a total value of several million euros (dollars)".