Italian police say they have seized large quantities of illegal fireworks in a nationwide crackdown ahead of Saturday's New Year's Eve celebrations.

Police say hundreds of thousands of illegal fireworks have been confiscated during the month of December.

They say fireworks have been seized in Rome, Turin, and Bari, but the bigger stashes are expected to turn up in Naples, where the most dangerous fireworks have been found.

On Friday, police displayed on state television a firework device known as “the spread,” which they say has the power to level a house if exploded indoors.

The name of the device is derived from a term used in financial circles to refer to the difference in interest rates between Italian and German bonds.

Several cities have imposed bans and restrictions on fireworks in an effort to curb the number of injuries suffered during end of the year celebrations.