The previously sporadic protests became a wave after authorities in northern city Bergamo on Monday ordered firefighters to remove a banner reading “You're not welcome” ahead of the minister's visit.

Firefighers removing the protest banner ahead of Salvini's visit to Bergamo on Monday. Photo: Giorigio Gori/Twitter

Photo and video footage of the removal went viral, triggering widespread anger and concerns about attempts to curb freedom of expression and peaceful protest.

In response, protestors hung hundreds of similar protest banners in the city of Campobasso on Wednesday ahead of Salvini's rally,

Protests continued in Naples on Thursday, where Salvini received an even colder reception from residents angry about the minister insulting southern Italians.

A banner reading 'Naples renounces Salvini' on an apartment building in the city yesterday. Photo: Carlo Hermann/AFP

The wave of protest comes as the social-media obsessed anti-immigrant League party leader continues his tour of Italy, frantically campaigning ahead of next week's European parliamentary elections.

Banners across Naples told Salvini he wasn't welcome ahead of his arrival for a securty meeting in the city, and riot police were sent in to quell protests as anti-League demonstrators gathered in a city square.

“Salvini go home!”, “Naples doesn't want you!”, “No to the minister of hate”, read some of the banners hanging from the city's famed balconies.

Many banners in Campobasso, Naples and elsewhere made references to “terroni”, a derogatory word equivalent to “rednecks” or “country bumpkins” that Salvini has used to describe southerners.

Salvini frequently derided southern Italians before his northern-separatist party, formerly known as the Northern League, became a national entity, chasing votes across the country with its “Italians first” slogan.

The minister has been widely mocked on social media, as Twitter users post photos of their favourite protest banners under the hashtag #Salvinitoglianchequesti (Salvini take these down as well)

“When are you going to work?” asked other banners, after Italian daily La Repubblica revealed this week that Salvini had spent just 17 days at the interior ministry so far this year.

A protest banner reading 'Salvini racist not in my name'. Photo: Carlo Hermann/AFP

Other banners goaded the nationalist about the 49 million euros of misspent public money that his party is supposed to pay back in instalments, or the Zorro toy Salvini revealed this week was stolen from him as a child.

“Some of the banners make me laugh,” Salvin tweeted, claiming that there have been 126 banners this year containing “insults and death threats”.

Protestors also continue to play photo and video pranks on the minister while he thinks they're posing for selfies.

The trend took off after two women kissed in a photo with the minister, known for his anti-LGBT views, and police seized the phone of a woman who made a video of herself asking Salvini whether he still thought southerners were “terroni”.

Meanwhile, prosecutors in Rome have opened an investigation following allegations in Italian media that Salvini has been misusing police aircraft to attend League party rallies around Italy. The minister denies any wrongdoing.

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