By Jan Strupczewski
BRUSSELS (Reuters) - Euro zone finance ministers will discuss the details on Monday of how to strengthen Europe's financial safety net, after their leaders decided on Friday the emergency fund should have more firepower and flexibility.
The ministers will mainly be putting the finishing touches to a comprehensive package of measures already outlined on March 11, aimed at ending the year-old sovereign debt crisis and preventing a new one from happening.
The measures agreed by the leaders still need formal approval at the next EU summit on March 24-25 but seem to address most of the market's concerns.
"In our judgment the overall impact on EMU (euro zone) sovereign risk premia should be, at the margin, positive," Goldman Sachs investment bank said in a research note.
IHS Global Insight chief euro zone economist Howard Archer said market pressure on Greek, Portuguese and Irish bonds was likely to ease for now.
The leaders agreed on Friday that the effective lending capacity of the euro zone rescue fund, the European Financial Stability Facility (EFSF), should be raised from the current 250 billion euros to the nominal value of 440 billion euros.
The effective capacity of the EFSF is now lower than the nominal value, because not all euro zone countries issuing guarantees have the triple A rating that the fund wants.
Euro zone ministers will discuss on Monday how to achieve the higher lending capacity, but a euro zone source involved in the discussions said the likely solution was that all euro zone countries would raise their guarantees for EFSF borrowing.
These guarantees, on a pro rata basis, now stand at 120 percent of a country's share in the capital of the European Central Bank.
The ministers will also have to decide how to implement other changes to the fund agreed by the leaders -- allowing the EFSF to buy bonds of distressed sovereigns at primary bond auctions and lowering the interest rate charged for the loans.
The ministers will be joined later in the day by finance ministers from the 10 European Union countries that do not use the euro and together they will discuss the technical aspects of setting up the successor to the EFSF, the European Stability Mechanism, which will become operational in mid-2013.
Euro zone leaders would like the ministers to decide on the appropriate mix of paid-in capital, callable capital and guarantees that will back the ESM's 500 billion euro effective lending capacity, and on the timetable for paying it.
The ESM will provide financial help to euro zone countries that are solvent but have liquidity problems, after a unanimous decision by euro zone countries and on the basis of a debt sustainability assessment by the European Commission, the IMF and the ECB.
Like the EFSF, the ESM will be able to intervene in the primary bond market and the price of its loans will be in line with IMF pricing principles.
But if the IMF and the Commission decide a country's debt is unsustainable, the government will have to negotiate a debt restructuring deal with its creditors.
To facilitate that, all bonds issued in the euro zone from mid-2013 will carry collective action clauses that prevent minority bond holders from blocking a restructuring deal for the majority.
EU finance ministers will end their day with a discussion on tougher EU budget rules and a mechanism to monitor and correct macro-economic imbalances in the single currency area.
(Reporting by Jan Strupczewski, editing by Tim Pearce)