A day ahead of the vote a Spanish newspaper published photographs of topless women and a naked man sunbathing at the president's villa.
Berlusconi called the photos in El Pais an invasion of privacy and his lawyer has threatened legal action against the newspaper.
Mirek Topolanek, the former Czech prime minister, admitted that he was the man in the photo but said that it had been doctored.
'Plebiscite' on Berlusconi
James Walston, a political science professor at the American University of Rome, said that Berlusconi had "succeeded in making the European election a plebiscite on him".
"Most Italians are voting on whether or not they like the government, there is very little that is a European issue."
The mud-slinging in the build up to Italy's vote has offered pollsters some excitement in an election that has been largely ignored by the electorate.
Over 375 million people are eligible to take part in the elections, but voter turn out has been low.
In Slovakia, the last opinion poll put voter turnout at 14 per cent, after only 17 per cent took part in elections in 2004, when the country had the lowest turnout among EU member countries.
Turnout has fallen with each EU election since the first in 1979, despite the growing role the parliament plays in adopting, amending or rejecting laws.
Only in Malta is voter turnout is expected to be high, topping 80 per cent, by far the highest average poll in the EU.
Opinion polls suggest the low turnout could see some gains for Europe's extreme right and left.
In the Netherlands on Thursday, the Party for Freedom, the party of controversial right-wing politician Geert Wilders, won 17 per cent of the vote, taking four seats in the European parliament.
The 45-year-old firebrand politician has declared himself on a mission to fight the "Islamisation" of the Netherlands.
In Latvia, parties faced municipal and EU elections, with the five government parties set to take a battering in the vote.
Some pollsters have said the votes could affect the stability of the ruling coalition, but the government has played down chances of a political shakeup to add to the country's economic woes.
Latvia has been hit particularly hard by the global economic crisis, leading many to believe Latvia will have to abandon its currency links to the Euro.
The government and central bank have strongly denied any devaluation plan is part of an IMF-led $10.63bn bailout agreed last year.