By Philip Pullella
ROME (Reuters) - Nearly three-quarters of Italians think ex-prime minister Silvio Berlusconi should be barred from the Senate after a conviction for tax fraud, and a majority want to avert a government crisis over the issue, according to a poll published on Friday.
The issue threatens the survival of the fragile ruling coalition because Berlusconi's supporters have threatened to pull out of Prime Minister Enrico Letta's left-right government if Berlusconi loses his seat.
The full upper house is expected to vote next month on whether to expel Berlusconi, a billionaire media tycoon who has served as prime minister four times.
A cross-party Senate committee is expected to continue sitting next week before voting on whether to start expulsion proceedings, which would end with a full vote on the floor of the Senate.
According to a poll by the SWG institute for the state television station RAI, 73 percent of Italians asked said they believed the Senate should vote to expel Berlusconi.
Sixty percent of those asked in the poll said the centre-right should continue to support Letta's government for the good of the country even if Berlusconi is booted out.
The poll indicated that centre-right voters were split almost down the middle about what to do if Berlusconi is ousted.
Fifty-two percent of centre-right voters said the bloc should withdraw its support for Letta, potentially forcing him to resign. But 45 percent said they should continue to support him and 3 percent were undecided.
Letta has repeatedly said that a government crisis in the current tough economic circumstances would be irresponsible.
Italy is struggling to control its 2 trillion euro public debt, and the drawn-out impasse over Berlusconi's fate has hurt efforts to reform the euro zone's third-largest economy.
Letta's centre-left Democratic Party (PD) has the largest presence on the 23-member committee that will make the recommendation on Berlusconi's fate to the full Senate.
A collapse of the four-and-a-half-month-old government could trigger early elections unless the PD can form a government with other political forces, such as dissidents from the anti-establishment Five Star Movement.
Berlusconi's supporters have sought to halt the hearings pending an appeal to the European Court of Human Rights, but have been rebuffed by the centre-left, which says the appeal is no more than a delaying tactic.
A separate SWG poll on Friday indicated that approval of Letta's government had risen to 29 percent from 25 percent a week ago and that his personal approval rose to 41 percent from 40 last week.
Italy's top court definitively convicted Berlusconi, 76, last month of tax fraud conspiracy at his Mediaset television empire. It sentenced him to a four-year jail term, commuted to one year under house arrest or in community service.
Berlusconi and his supporters say he is innocent and that magistrates whom they accuse of being politically motivated are trying to end his 20-year domination of Italy's political scene.
He says the centre-left will not be impartial in the Senate committee vote but rather use it to get back at their traditional political enemy.
(Editing by Mark Heinrich)