Thousands of migrants sail to Italy from North Africa every year
Italian MPs have backed a plan to fine illegal immigrants up to 10,000 euros ($13,000), as the government continues to tighten immigration controls.
The lower house overwhelmingly backed the bill, which also proposes jailing those who rent houses to illegal immigrants for up to three years.
The bill still needs to be approved in the Senate before it can become law.
Italy has just introduced a policy of returning boatloads of migrants to Libya before they can claim asylum.
The move has attracted criticism, with the UN's refugee agency and the Vatican both saying the move was a breach of international law.
Prime Minister Silvio Berlusconi sparked further controversy when he defended the decision by saying he did not want to see a "multi-ethnic" Italy.
"The left's idea is of a multi-ethnic Italy. That's not our idea, ours is to welcome only those who meet the conditions for political asylum," he told a news conference at the weekend.
The government says it faces an unmanageable flood of immigrants, many arriving on outlying islands which do not have the means to cope.
More than 36,000 migrants landed on the shores of Italy last year - an increase of about 75% on the year before.
The BBC's Duncan Kennedy, in Rome, says many Italians believe their country is being left on its own by the European Union to deal with the problem of immigration.
And many are now ready to support stricter measures to control the flow of people into their country, our correspondent adds.
Mr Berlusconi's centre-right coalition ensured the bill's speedy passage through lower house by turning it into a vote of confidence in the government.
While 316 MPs backed the bill, 258 voted against. It will now go to the Senate.
Rocco Buttiglione, a centre-right MP, said the law would bring "slavery" to Italy by creating a class of workers without any rights.
He warned that rather than turning to police when they need to, migrants would turn to the Mafia or vigilante justice.
Other measures in the government's security and crime legislation include a register of homeless people, citizens' vigilante patrols, and up to three years in prison for anyone who insults the police.
Critics say the right-wing government is targeting especially immigrants and Roma (Gypsies).
But Manuela del Lago of the anti-immigrant Northern League party, which spearheaded the legislation, said Italy was embarking on the right path.
"We don't understand why we have to keep them all here and in other countries they don't take anyone," she said.