Mr Berlusconi was joined by his ministers and regional candidates
Tens of thousands of people have staged a rally in Rome in support of Italian Prime Minister Silvio Berlusconi, ahead of regional elections this month.
Mr Berlusconi's People of Freedom party was dealt a blow when it was excluded from the vote in the key Rome region after failing to register on time.
He blamed dirty tricks from magistrates and the opposition for the exclusion.
A string of sex and corruption scandals have weighed heavily on Mr Berlusconi in the past 12 months.
The latest is accusations that he was trying to block political talk shows on television critical of his government.
After the alleged interference was picked up using phone taps, prosecutors last week said they would investigate him for abuse of power.
He also faces two trials, for tax fraud and bribery. Mr Berlusconi denies any wrongdoing.
Addressing the crowd from a stage emblazoned with the party's new slogan - "Love conquers hatred and envy" - Mr Berlusconi launched a blistering attack on his political enemies.
He said left-leaning judges and centre-left politicians were out to get him in "a laughable investigation based on the tapping of my calls".
He also decried what he said were dirty tricks to exclude his party from the election race, and said he wanted to preserve freedom and democracy for Italy.
On Saturday, an Italian court rejected the party's latest appeal to be reinstated in the central Lazio region, which includes Rome.
Italy's opposition denounced the rally.
"This is the only government in the world in which the head of the government rallies against magistrates," Pierferdinando Casini, head of the Catholic UDC party, told the AFP news agency.
Berlusconi supporters said that 1m people attended the event, a week after last Saturday's anti-Berlusconi march in the city.