ROME (AFP) - Italy's centre-left opposition Monday ousted Prime Minister Silvio Berlusconi after an acrimonious election campaign, exit polls showed, ending the tycoon's flamboyant five-year hold on power.

While officials of Romani Prodi's campaign refused to declare victory yet, supporters flocked to his campaign's headquarters voicing both jubilation and relief.

"We're still very cautious, but if these indications are confirmed, that would mean that Italy had decided to turn the page and begin a new era," said one spokesman at Prodi's headquarters.

A Nexus poll for state broadcaster RAI gave his multi-party coalition -- which includes Communists as well as Catholics and liberals -- a majority in both houses of parliament.

It showed the centre-left bloc with 50 to 54 percent of the vote for both the lower Chamber of Deputies and upper house Senate against 45-49 percent for Berlusconi's House of Freedoms coalition.

There was no immediate reaction from Berlusconi, but Senator Paolo Guzzanti of his Forza Italia party told AFP: "Our coalition has lost the elections.

"We expected something like this because we've lost every (local) election since 2001."

The exit polls were released within minutes of the close of voting at 3:00 pm (1300 GMT) after a two-day general election.

First official results were due later Monday.

"Under Berlusconi I lost my identity as an Italian. I want to rediscover my pride in being Italian, and not to be ashamed anymore to tell foreigners where I'm from," said Marcella Giunci, 50, a Prodi supporter.

"Prodi has given me back my dignity back," she told AFP.

The exit polls forecast a collapse of the Forza Italia share of the vote to between 20 and 23 percent, against 29.4 percent it took when Berlusconi swept to power in 2001.

"The exit polls are unfavourable, but we are remaining very cautious," said Forza Italia campaign analyst, Denis Verdini.

"What's interesting for us is that the turnout figure is above 83 percent, which is very good for us," he added.

"One vote could make all the difference in the Chamber of Deputies."

Berlusconi's allies, the National Alliance of Gianfranco Fini held up its vote, at about 12.5 percent, and the Christian Democrat UDC of Pier Ferdinando Casini took between five and seven percent, according to the exit polls.

Earlier, the usually reserved Prodi -- a 66-year-old economist who unseated Berlusconi in the 1996 election -- told AFP he was "confident, very confident" of maintaining his hex on the media magnate.

In the afternoon, his office announced he would address supporters in the square outside his headquarters at 6:30 pm, and later, a victory rally in the city's huge Piazza del Popolo. Battista Gaspari, 45, an Italian living in Germany who came home to vote, said: "With Prodi, Italy will rediscover its unity."

"What hit me most about life under Berlusconi was that culture was debased, especially television, and that the economy deteriorated."

Berlusconi, Italy's richest man, remained at his private mansion in Arcore, outside his native Milan. The ANSA news agency said he would return to Rome later Monday to follow the count at his official residence.

Prodi's coalition prevailed after a vitriolic election campaign in which he highlighted unemployment, crime, the economy and the war in Iraq, for which he blamed Berlusconi for involving Italy in the US-led coalition.

In a campaign focused on the country's dire economic performance, Berlusconi hoped to swing the vote by promising to abolish a home-owners council tax.

Prodi pledged to revive an inheritence tax, but after pressure from the centre-right clarified that this would only be for the rich. He also promised to cut taxes on employers to reduce the cost of labour.

Most of all, the campaign was characterised by insults, notably Berlusconi's use of a vulgar term to describe centre-left voters.

Pollster Andrea Vannucci said it may have backfired by encouraging people tired of his bombastic style to vote against him.

While Berlusconi tried to galvanize Italians with a grand vision of a more prosperous future, Prodi based his campaign on cleaning up the public finances and promises of a return to morals, a dig at the premier's constant brushes with the courts over his business activities.

A former European Commission head and university economics professor, Prodi banked on these credentials to win over an electorate that felt let down by Berlusconi's failure to apply his formidable business acumen to solving Italy's deep-seated problems.