Italian police have seized an air-to-air missile and a huge stash of automatic weapons during raids on far-right groups, officials have said.

Three men were detained, including one linked to a neo-fascist Italian political party.

Police said the discoveries stemmed from a previous investigation into Italians who took part in the Russian-backed insurgency in eastern Ukraine.

In a statement, Turin police said one of the arrested men had run unsuccessfully as a Senate candidate for the neo-fascist Forza Nuova party in 2001.

At his home in Gallarate, police found nine assault weapons, nearly 30 hunting rifles, pistols and bayonets as well as ammunition and antique Nazi plaques featuring swastikas.

Police stand by a missile seized at an airport hangar near Pavia, northern Italy (Tino Romano/ANSA via AP) (AP)

Two other men were detained after police found a French-made missile at an airport hangar that they apparently were seeking to sell.

The missile reportedly came from Qatar.

A large cache of guns and ammunition was seized by the Turin special police force, along with Nazi plaques (FRANCESCO AMMENDOLA and HO/Polizia di Stato/AFP)

Police also uncovered several pieces of Nazi memorabilia (HO/Polizia di Stato/AFP)