Authorities arrested 22 people including a father and son team of Austrian gunsmiths who illegally supplied the Naples-based syndicate with weapons that had their serial numbers removed.

"This clan armed itself to start a war with other clans," Naples prosecutor Ivana Fulco told a news conference at the EU judicial agency Eurojust, in The Hague.

The year-long Italian investigation involved the arrests of several Camorra couriers, with the trail eventually leading to the two Austrian gunsmiths, she said.

The Austrians are known to have sold more than 800 new pistols to the Italian mafia group as well as 50 Kalashnikov assault rifles and 10 'Scorpion' submachine guns, worth a total of 500,000 euros ($565,000).

Nearly 100 further weapons and a "huge" quantity of ammunition were found hidden in several premises in Austria, Eurojust said.

"Some of these are weapons of war," said Filippo Spiezia, the national member for Italy at Eurojust.

One of the arrests was in France, where the Camorra network was also trying to buy weapons, prosecutor Fulco said.

The Camorra is one of Italy's three main organised crime groups, along with Sicily's Cosa Nostra, commonly known as the mafia, and the 'Ndrangheta, centred in the Calabria region.

In December Eurojust announced the arrest of around 90 suspected 'Ndrangheta mobsters in six countries in Europe and South America.