Naples police collected more than 1,000 pounds of fireworks and arrested Vincenzo Vitagliano, 28, and Natalino Fiengo, 35, ANSA reported.
Investigators said the two men had 230 different types of fireworks in the trunk of a car.
In the Sicilian city of Siracusa, police confiscated about 550 pounds of fireworks, estimated to be worth about $10,500, that came from Russia.
Officers in Rome arrested a 55-year-old man who was allegedly taking orders for illegal fireworks and delivering them door-to-door. They also seized about 330 pounds of fireworks.
In the southern Italian city of Lamezia Terme, police confiscated 317 pounds of "highly explosive" illegal fireworks from the garage of a woman in a residential neighborhood.
Many people are injured each year by New Year's Eve fireworks, ANSA said.
Near Florence Sunday night, a 42-year-old man lost an eye when he set off a firecracker in a metal tube. He was apparently setting up a New Year's Eve fireworks display.
In Naples Sunday, a car packed with fireworks exploded, causing injuries to the driver, a passenger and the operator of a passing bus.