The confrontation took place when Salvini visited a neighbourhood of Mondragone, the scene of tensions last week between some residents and foreign workers following an outbreak of the coronavirus in the area.
When Salvini arrived an hour later than scheduled there was a hostile crowd waiting for him, many of them shouting insults.
Salvini, wearing a face mask in the colours of the Italian flag, quickly lowered it to begin his speech, but could scarcely be heard over the heckling.
“Salvini is worse than the Covid,” some shouted, with others calling him a “jackal” or a “clown” and telling him to leave.
Salvini, as he tried to continue his speech from behind a police line, was forced to dodge eggs and water thrown from the crowd, which was held back by riot police.
Matteo Salvini in Mondragone on Monday. Photo: Filippo Monteforte/AFP
Some 700 residents of five apartment blocks on a council estate, mostly home to Bulgarian workers, were placed under quarantine after a cluster of cases was detected there last week.
After protests by residents, many of whom said the lockdown left them without money for food, violence broke out between the protestors and Italians liviing nearby who threw stones at the migrants, who they blamed for the outbreak.
Television footage also showed several vehicles belonging to Bulgarians damaged, their windscreens smashed and the Bulgarian-registered plates taken as trophies.
Last Friday, riot police and soldiers were sent to the town to restore order.
Italy's far-right aimed to capitalise on the drama. As Matteo Salvini organised a visit, his League party issued a press statement calling the town a “social bomb”. Giorgia Meloni, head of Brothers of Italy, lashing out at the government for failing to “control the migrants”.
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Salvini served as interior minister and deputy prime minister in the last coalition government, pursuing hardline policies that were hostile to immigrants.
His party – formally known as the Northern League, and previously also hostile to southern Italians, as well as non-Italians – has in recent years begun to attract voters in the south after its rebrand.
However, his visits to Naples and other parts of southern Italy regularly spark protests.
With the collapse of that administration last year after his failed bid to take power, and the coronavirus crisis this year, his profile – and his standing in the opinion polls – has fallen.
In brief comments to television crews at the scene, he denounced what he claimed were agitators who had come in from outside.
“We have to guarantee the rights of Italians, and expel foreigners without papers,” he told AFPTV. “We need to invest more in the Naples region, in resources and in the forces of order,” he added.
He left the scene after half an hour, but promised to return.