Prime Minister Mario Monti faces a testing week seeking to shore up Italy's strained public finances, with an IMF mission expected in Rome and market pressure building to a point where outside help may be needed to stem a full-scale debt emergency.
Monti is expected to unveil measures on December 5 that could include a revamped housing tax, a rise in sales tax and accelerated increases in the pension age. But pressure from the markets could force him to act more quickly.
One source with knowledge of the matter said contacts between the International Monetary Fund and Rome had intensified in recent days as concern has grown that German opposition to an expanded role for the European Central Bank could leave Italy without a financial backstop if one were needed.
The source said it was unclear what form of support could be offered, such as a traditional standby arrangement or a precautionary credit line, if a market selloff Monday forced immediate action.
The IMF inspection team is expected to visit Rome in the coming days but no date has been announced.
An unsourced report in Italian daily La Stampa said up to 600 billion euros could be made available at a rate of between 4-5 percent to give Italy breathing space for 18 months.
Such a sum would be beyond the IMF's current capacity and would need new measures such as the issue of new special drawing rights (SDRs) or intervention by the ECB, it said.
The Fund's total lending capacity is currently around $400 billion (258 billion pounds).
The IMF declined to comment on any moves to provide financial support, and official sources in Rome said they were unaware of any request for assistance from Italy, which has over 185 billion euros of bonds falling due between December and the end of April.
Italy's borrowing costs have returned to the dangerous levels that triggered the collapse of former Prime Minister Silvio Berlusconi's centre-right government, with yields on 10 year bonds ending last week at more than 7.3 percent.
Italian yields are now in the territory that forced Greece, Ireland and Portugal to seek international bailouts and an auction Tuesday of up to 8 billion euros of BTP bonds will be a crucial test.
Friday, Italy paid a euro lifetime high yield of 6.5 percent to sell new six-month paper, a level which analysts said cannot be maintained for long without pushing a public debt amounting to 120 percent of gross domestic product out of control.
Italy, the euro zone's third biggest economy, would be far too big for existing bailout mechanisms and default on its 1.8 trillion euro debt would cause a banking and financial crisis that would probably destroy the single currency.
Monti outlined the broad thrust of his reform plans earlier this month, promising a mix of budget rigour and reforms to stimulate economic growth, and has stuck to Berlusconi's pledge to balance the budget by 2013.
But with growing signs that Italy's chronically sluggish economy could be entering recession, he has come under pressure to provide concrete details quickly.
The measures outlined so far are broadly in line with directions previously given by the ECB, but there have been no detailed discussions with international bodies on the kinds of conditions normally attached to IMF assistance programs.
As well as loosening job protection measures, privatising local services and opening up professions to more competition, additional budget measures estimated by Italian media at up to 15 billion euros could be announced.
Monti can take some comfort from surveys showing broad popular support for his technocrat government, but austerity measures have yet to bite deeply and surveys also show a mixed picture on individual austerity measures.
On pensions, the government is expected to bring forward an already-planned increase in retirement ages, with a wider reform possible in the coming weeks.
Monti may reintroduce a housing tax that was scrapped by Berlusconi in a last-minute campaign pledge before the 2008 election. The move cost the Treasury an estimated 3.5 billion euros a year.
Other ideas under consideration include raising the value-added tax band in bars and restaurants, which currently stands at 10 percent.
(Additional reporting by Gavin Jones and Steve Scherer and Lesley Wroughton in Washington; Editing by David Stamp and Alessandra Rizzo)