European finance ministers were warned on Tuesday night that Italy's liquidity crisis could leave the eurozone's third biggest economy insolvent with devastating impact on the fate of the single currency and its big core economies, Germany and France.

Eurozone finance ministers met in Brussels in their latest attempt to plot a path out of the EU's worst crisis. With Mario Monti, the new Italian prime minister and finance minister, reporting to the session on his austerity package aimed at saving Italy and shoring up the euro, a confidential report from the European commission and the European Central Bank said Monti would need to do more than already promised.

The report, obtained by the Guardian, said Monti had to go further in his promises to combat rampant tax evasion in Italy, which is estimated to amount to 20% of gross domestic product.

"The sovereign debt crisis has now moved from the periphery to Italy and other core euro area countries. Pressure on Italian sovereign bond yields is particularly acute, reflecting investors' mounting concerns with the sustainability of Italy's large public debt" – almost €2tn, (£1.7tn) – the report said.

"The risks of a full-blown sovereign liquidity crisis can increase rapidly in the absence of a determined policy response … Persistently high interest rates increase the risk of a self-fulfilling 'run' from Italy's sovereign debt. A liquidity crisis could then turn into a solvency crisis, whose repercussions for other large euro area countries would be very acute given their exposure to the Italian economy."

Italy on Tuesday easily raised €7.5bn on the bond markets, but at exorbitant rates above the 7% sustainability threshold.

The European finance ministers were expected to agree to release €8bn in bailout funds to Greece, the latest tranche, after months of haggling over whether Athens had done enough to warrant the receipt and the fall of the Papandreou government. Klaus Regling, head of the European financial stability facility, the main bailout fund, was expected to disappoint the 17 governments by telling them there was little chance of leveraging the €250bn pot of money into a trillion-plus war chest by drawing in Asian investors and sovereign wealth funds.

The leveraging plan was drawn up by eurozone leaders at a summit a month ago. "It doesn't look like it will be [multiplied] 4-5 times," said a Brussels diplomat. "More like 2.5 times. That's probably not enough to restore confidence in Italy or Spain."

Tuesday night's meeting came ahead of another crucial summit of EU leaders next week at which Germany and France, while still at odds over central details, will launch a drive for a eurozone "fiscal union", with governments required to forfeit national powers over fiscal, budget, tax and spending policies to a eurozone body. Angela Merkel, the German chancellor, is the biggest obstacle to any prompt and radical action aimed at stabilising the bond markets and ring-fencing the euro. Others, led by France, want the European Central Bank to be given interventionist powers to defend the currency, print money, and act as lender of last resort as well as the pooling of eurozone debt through the issue of common euro bonds.

Merkel is fiercely opposed to both options, insisting instead on reopening the EU's Lisbon Treaty to entrench new disciplines and intrusive powers of scrutiny over eurozone national budgets. Rather than focus on solving the immediate crisis, Merkel's priority is to create a durable new system eliminating the chances of a recurrence. Launching eurobonds and empowering the ECB to intervene, said Wolfgang Schäuble, German finance minister, would mean "no European country would retain its triple-A rating". "The Germans want treaty change without eurobonds. The others want eurobonds without treaty change," said the diplomat. "In the end the Germans are in control of this."