It comes after a wave of violence against African farm workers in southern Italy which left some 70 people injured.
Police have evacuated hundreds of Africans by bus from the town of Rosarno, in Calabria.
Correspondents say the problem is closely related to organised crime in the region.
Pope Benedict XVI spoke out strongly in favour of the rights of poor African farm workers, who have been the target of violence in recent days.
About 70 people have been injured, including migrants, local residents and police officers trying to restore order.
“An immigrant is a human being, different only in where he comes from, his culture and tradition,” he told pilgrims gathered in St Peter’s Square at the Vatican.
I invite everyone to look in the face of those nearby and see their soul
Pope Benedict XVI
“He is a person to respect and with rights and responsibilities, and should be respected particularly in the working world where there is an temptation to exploit.”
“We have to go to the heart of the problem, of the significance of the human being,” the Pope said.
“Violence must never be a means to solve difficulties.
“The problem is a human one, and I invite everyone to look in the face of those nearby and see their soul, their history and their life and say to themselves: it is a man and God loves him as God loves me.”
The BBC’s David Willey in Rome says many of the migrants from north and west Africa have been earning starvation wages as fruit and vegetable pickers – backbreaking work which Italians do not want.
Many of the migrants have been living in squalid temporary camps
The labour market is controlled by the local mafia, called the ‘Ndrangheta, which is believed to employ ever growing numbers of illegal seasonal day labourers.
The workers live in sordid conditions and are paid very low wages, out of which they have to pay kickbacks to their bosses, says our correspondent.
Wages are handed out in cash, labour laws and safety and health regulations are ignored, and no taxes or welfare contributions are ever paid.
The Calabrian mafia has become one of the most powerful criminal organisations in Italy in recent years, controlling much of Europe’s narcotics trade.
Italy’s Interior Minister Roberto Maroni prompted a storm of criticism from the leftist opposition by suggesting that the violence was the result of not addressing the issue of illegal workers in the country.
“There’s a difficult situation in Rosarno, like in other places, because for years illegal immigration – which feeds criminal activities – has been tolerated and nothing effective has ever been done about it,” he said according to Italy’s La Repubblica newspaper.
Opposition leader Pierluigi Bersani said: “Maroni is passing the buck … We have to go to the root of the problem: mafia, exploitation, xenophobia and racism.”