Mr Berlusconi says he is the target of a politically motivated judiciary
Italy's lower house of parliament has voted to pass a controversial immunity bill put forward by Prime Minister Silvio Berlusconi's government.
The amendment protects top public officials, including the prime minister and president, from prosecution.
The bill is expected to be passed by the upper house, where Mr Berlusconi enjoys a solid majority, in September.
Critics have labelled the change a made-to-measure piece of legislation to protect the 71-year-old billionaire.
Mr Berlusconi - who was not present in parliament when the bill was passed - currently faces a corruption case involving one of his lawyers, David Mills, the former husband of a British cabinet minister.
'Rough and ready'
He also faces prosecution in Rome for alleged collusion between his Mediaset network and state broadcaster, Rai.
Opposition leader Walter Veltroni said the law was: "Objectively speaking, a law for a single person".
Mr Berlusconi has long claimed that the country's judiciary is politically motivated and is running a campaign against him.
He claims that he has attended 2,500 court hearings, had 587 police visits and spent some 174m euros (£135m; $271m) in legal fees since entering the political scene 14 years ago.
Former prime minister and opposition lawmaker Massimo D'Alema urged the prime minister to "hold his head high and face these judgements".
"This law is a rough and ready measure to block the corruption trial which the president is involved in and perhaps prevent another," he added, according to Italy's Corriere della Sera newspaper.
But Italy's Justice Minister Angelino Alfano defended the bill, which was passed by 309 votes to 236, with 30 abstentions.
"Having brilliantly won the elections, Silvio Berlusconi deserves to be able to calmly govern this government. And this country needs to be governed," he said, according to the paper.
Another bill reforming the justice system, which would freeze all trials for alleged crimes committed before 2002, is currently making its way through parliament.
Mr Berlusconi's government say it is a necessary step to speeding up the country's notoriously sluggish legal system but his critics have branded it yet another tailor-made law.
Judges have condemned his various changes to the legal system and have threatened to go on strike.