Cécile Kyenge is target of racist remark on Facebook by Cristiano Za Garibaldi, deputy mayor of Diano Marina in Liguria

An Italian politician has likened the country's first black minister, Cécile Kyenge, to a prostitute in the latest in a barrage of racist insults that has shed light on resistance in Italy to racial integration.

Cristiano Za Garibaldi, the rightwing deputy mayor of Diano Marina in Liguria, suggested on his Facebook page that Kyenge frequented an area used by prostitutes, many of whom are black.

Kyenge, 48, who was born in the Democratic Republic of the Congo and moved to Italy 30 years ago, has grown accustomed to the intolerance of rightwing Italian politicians, notably Roberto Calderoli, a former government minister with the Northern League party, who compared her to an orangutan in July. Since being appointed minister for integration in April, Kyenge has pushed for a law granting Italian citizenship to children born in Italy to immigrants, and more recently suggested second homes in Italy could be rented out to homeless people.

That provoked Za Garibaldi, as well as a northern Italian winemaker, Fulvio Bressan, who allegedly called Kyenge a "dirty black monkey" on his Facebook page last week, prompting a debate in the wine world about boycotting his wines.

As Italy experiences large scale immigration for the first time in its history, there have been episodes of benevolence, such as the human chain formed in the sea by bathers in Sicily this month to help migrants land in rough water from their beached vessel. But racist attitudes hold out on football terraces, particularly at Lazio in Rome where one section of stadium was closed at the weekend after racist chanting.

In May, Northern League member and European MEP Mario Borghezio predicted Kyenge would force "tribal conditions" on Italy and create a "bongo bongo" government. Africans, he added, had "not produced great genes".

In June a local councillor for the Northern League called for Kyenge to be raped, so she would understand the seriousness of the attempted rape of two women in Genoa by a Somali. Bananas were thrown at Kyenge during a speech in July.

Za Garibaldi repented on Sunday, saying his comments were "in bad taste and offensive", adding he had made them because he was under stress from having to pay high Italian taxes.

"This is the umpteenth episode in a constant attack that is not only targeted at me, but anyone in this country who dares to think differently," said Kyenge.