L-R: Greek Prime Minister Lucas Papademos, German Finance Minister Wolfgang Schaeuble and Dutch Finance Minister Jan Kees de Jager talk prior an Eurozone meeting at the EU Headquarters in Brussels.

After months of acrimonious debate, markets rose as all sides expressed confidence that an agreement would be found to greenlight a 230-billion-euro ($300 billion) financial lifeline, in exchange for strict surveillance of the government over coming years.

That despite grinding negotiations with private creditors on the sidelines of talks among finance ministers in Brussels, principally over a 5.5-billion-euro gap needing to be filled if Germany and the Netherlands especially are to get the agreement past their national parliaments.

Greece's Prime Minister Lucas Papademos and Finance Minister Evengelos Venizelos took turns scuttling in and out of talks with the representatives of the banks, officials said.

A mini-breakthrough was reached just after midnight (2300 GMT Monday) when national eurozone central banks agreed to engage in their own write-down of Greek bonds.

"There's a long way to go yet, but we wouldn't still be in there if we didn't think we would get there tonight," said one eurozone governmental source.

Greece, Germany, the IMF and the head of the Eurogroup of finance ministers, Jean-Claude Juncker, each maintained that a deal could be reached during the closed-door talks.

European Union and International Monetary Fund partners have set a target of reducing Greek debt levels to 120 percent of gross domestic product (GDP) by 2020, still steepling high but down from around 160 percent at present.

The 5.5-billion-euro gap comes about because the latest analysis suggests that even with a bailout, Greek total debt would only fall to 129 percent of GDP.

Venizelos said on arrival that he was "optimistic" of a deal, signalling "a long period of uncertainty coming to a close today -- a period that benefited neither the Greek economy, nor the euro area overall."

A "confident" Wolfgang Schaeuble, his German counterpart, seemed to echo the sense that an agreement was in the making late-afternoon, while IMF chief Christine Lagarde also praised Athens' "great efforts" to overhaul its economy.

But Dutch Finance Minister Jan Kees De Jager signalled a long night ahead when he demanded that the EU and the IMF take "permanent" control of decision-making over revenues and public expenditure in Greece.

De Jager said partners committed to providing Greece with money for years to come need "some kind of permanent presence" dictating policy on the ground, saying lenders should be "the boss."

The Greek rescue plan under discussion is structured as follows:

-- a writedown of privately-held government debt worth 100 billion euros;

-- a series of sweeteners for Greek banks, and guarantees in case private creditors do not take up the bond-swap offer to be launched on Wednesday in sufficient numbers;

-- and loans eventually adding up to another 130 billion euros.

Athens faces debt repayments of about 14.5 billion euros on March 20, otherwise it could be classed as bankrupt.

Full delivery of the rest of the package, as well as IMF assistance, will be contingent on Greece enacting deeply unpopular spending cuts and reforms demanded by its partners.

Belgian Finance Minister Steven Vanackere and others warned that Greece must deliver, "not only today, but in the weeks, months and years to come."

Eurozone hardliners' patience with Greece almost snapped over recent weeks with growing suggestions Athens could be cut adrift and that the eurozone would suffer less damage from such an approach than 18 months ago.

Many euro partners see Greece as the victim of decades of chronic financial mismanagement by dynastic political forces -- what Italian Prime Minister Mario Monti last week called a "perfect catalogue" of errors.

Ahead of a general election in April, the new bailout has been likened to the aid equivalent of a hospital drip.

Surveillance of Greece's day-to-day economic management is critical after the failure of an initial 110-billion-euro EU-IMF rescue approved nearly two years ago.

A small army of EU officials is building up in Athens to make sure Greece delivers on pledges including a 22 percent reduction in the country's minimum wage and a 12-percent cut to pensions of more than 1,300 euros a month.

On top of 3.2 billion euros in the latest spending cuts, Greece has agreed in principle to open a blocked, or "escrow" account to ensure that aid for repayments to government creditors is set aside and not used for other purposes.

After repeated violent protests, finally resolving the Greek problem would allow eurozone leaders to focus on building a financial firewall for the currency bloc as a whole at a March 1 and 2 summit.