| Silvio's supporters in the senate will move a confidence motion while opponents will seek a no-confidence vote [AFP]
The Italian prime minister has addressed parliament ahead of a crucial no-confidence motion, with political commentators predicting he has slim chances of surviving it.
"We need continuity; operational continuity to have an efficient government; institutional political co-operation," Silvio Berlusconi said on Monday.
Tuesday's vote in both the chamber of deputies and the senate could be decided by as little as a single vote, political commentators said.
Analysts have estimated that the 74-year-old leader may just have the numbers to survive with 314 possible votes against 313 for the combined opposition.
Berlusconi, a media baron, said Italy needed "everything except a dark crisis", adding that "what's certain in our political system is that today the Italian people are deeply rooted and can choose who they wish to be governed by at all levels".
"If the government has to operate well, it must be left to people to decide and this is part of our constitution and sovereignty," he said.
"If this principle is violated, then it means that the spirit has been betrayed. And those in parliament have to interprete the wish of the people."
The vote comes as Berlusconi - accused of paying for sex and paying the Mafia to protect his family and busines interests - wades through one of his toughest years in 2010, an "annus horribilis" of scandal and bitterness that has undermined his leadership and left his struggling centre-right government in disarray.
A split with a group led by Gianfranco Fini, his former ally, in July cost him a secure parliamentary majority and after months of stalemate, a no-confidence motion in parliament seems likely to be decided by just one or two votes.
A no-confidence motion will be brought by opponents in the lower chamber of deputies and a confidence motion by supporters in the senate.
Guido Moltedo, a political commentator in Rome, told Al Jazeera that the vote was a "turning point" for Italy "even if Berlusconi succeeds in having a majority [of the vote]".
"Everything is going to change ... in this country; and the confusion will be great according to me in both cases: if Berlusconi wins a majority or if he loses the confidence vote," he said.
"Berlusconi can go away in the near future but the situation is the country will not be much better ... because the opposition is fragmented and fractious."
The prime minister has been predicting he will win, but if he loses he will have to resign, halfway through the five-year term of parliament.
The government has also been increasingly hopeful of getting through.
"I am optimistic," Roberto Cota, governor of the Piemonte region and a leading figure in Berlusconi's Northern League coalition partners, told SkyTG24 television on Sunday.
However Fini, the premier's former ally, said Berlusconi would likely lose and that he was fighting to cling to power solely to avoid criminal trials related to his business empire.
The result may depend on last-minute changes of heart or outside factors such as whether any of three pregnant deputies expected to vote against the government have to be absent from the chamber.
The vote will be closely watched on bond markets which are on high alert over the euro zone debt crisis and which could turn on Italy, one of the most heavily indebted countries in Europe, if the situation threatens financial stability.
Even if Berlusconi scrapes through, there is little confidence that he will have the strength to push through the kind of reforms authorities such as the Bank of Italy believe are needed to address deep-seated problems in the economy.
An alarming jump in the premium investors demand to hold Italian debt rather than benchmark German bonds last month underlined the danger, although the interest rate spread has since come back from the record levels it hit on November 30.
"However it finishes, there are grounds to be sceptical about the immediate future of the country," Il Sole 24 Ore, the financial daily often seen as the mouthpiece of the Italian business establishment, wrote in an editorial on Sunday.