ITALY'S largest mafia trial in more than 30 years is set to begin on Wednesday, as prosecutors hope to strike a blow to the 'Ndrangheta crime syndicate, whose tentacles reach worldwide.

More than 350 alleged members of the mafia and the politicians, lawyers, businessmen and others accused of enabling them face a judge in a huge, specially converted courtroom in the southern Calabrian town of Lamezia Terme, in the heart of 'Ndrangheta territory.

Prosecutors are seeking to prove a web of crimes dating back to the 1990s, both bloody and white-collar, including murder, drug trafficking, extortion, money laundering and abuse of office.

The trial "is a cornerstone in the building of a wall against the mafias in Italy", anti-mob prosecutor Nicola Gratteri told AFP.

In Italy, so-called "maxi-trials," which include scores of defendants and countless charges, are seen as the best judicial resource against the country's various organised crime groups, of which the 'Ndrangheta is now considered the most powerful, controlling the bulk of cocaine flowing into Europe.

The most famous "maxi-trial" of 1986-7 dealt a major blow to Sicily's Cosa Nostra, resulting in 338 guilty verdicts, but prosecutors Giovanni Falcone and Paolo Borsellino were later assassinated by the mob.

The current trial, expected to last at least a year and likely longer, features 355 defendants, more than 900 prosecution witnesses, and an unprecedented number of collaborators, given the close family ties within the 'Ndrangheta that discourage turncoats.

- 'Like a multinational' -

The 'Ndrangheta has expanded well beyond its traditional domains of drug trafficking and loan sharking, now using shell companies and frontmen to reinvest illegal gains in the legitimate economy.

In many parts of Calabria, it has infiltrated practically all areas of public life, from city hall and hospitals, to cemeteries and even the courts, experts say.

Authorities believe there are some 150 'Ndrangheta families in Calabria and at least 6,000 members and affiliates in the region. That swells to thousands more when including those worldwide, although estimates are unreliable.

The organised crime group generates more than 50 billion euros ($61 billion) per year, according to Gratteri, who called it the world's richest such organisation.

The prosecutor explained the 'Ndrangheta as a network of families, each of which wield power over subordinates.

"I have to start with the idea that there's an organisation, as in a business, as in a large multinational, with a boss and then down, like a pyramid, to all the other members," Gratteri told AFP, explaining the need for the "maxi-trial".

- Rubbing shoulders with the state -

The current trial focuses on one family, the Mancuso group, and its network of associates who control the Vibo Valentia area of Calabria.

The town of Lamezia Terme, where the trial will take place, was cited in a 2008 parliamentary organised crime report as a public safety emergency zone where the region's "greatest increase in serious bloodshed has been recorded".

Defendants include a high number of non-clan members, including an ex-parliamentarian, a high-ranking police official, mayors and other public servants and businessmen.

"The impressive thing is... the power the Mancuso gang has shown in rubbing shoulders with state apparatuses, which were literally at their disposal," Gratteri said following a wave of arrests in December 2019 throughout Italy and Europe that led to the trial.

Criminologist Federico Varese of Oxford University said the trial reflects the wide-reaching control of the 'Ndrangheta, who are embedded in the community and involved in every legal and illicit activity.

"The real strength of these mafia families is they have control of the territory and within the territory they do everything," said Varese. "If you want to open a shop, if you want to build anything, you have to go through them."

"They are the authority."