Lawmakers were under increasing pressure after the international ratings agency Fitch downgraded its assessment of Greece's long-term debt and said it considered a Greek default "very likely."
In Athens, parliamentary committees began by taking up a bill that outlined rules and procedures for debt restructuring with private creditors, and which was expected to be voted later in the day, assembly sources said.
The government hopes that 66 percent of private creditors will sign up to a bond swap deal, allowing Athens to impose a collective action clause (CAC) to force hold-outs to accept losses as well.
Last Tuesday's eurozone accord provides Athens with loans worth 130 billion euros ($172 billion) to 2014, and a 53.5 percent writedown of privately-held Greek sovereign debt.
The second measure should slash 107 billion euros from the country's debt mountain of 350 billion euros.
In Asia, the euro traded slightly stronger against the dollar and yen but stocks were mixed as positive sentiment sparked by the bailout agreement gave way to concern over Athens' ability to carry out much-needed cuts.
One reason for trader's unease was Fitch's announcement that it expected Greece to default on its debt repayments "in the near term."
In Washington, an International Monetary Fund official acknowledged that IMF participation in a second Greek bailout was essential to make it work.
But he also told media that the complex 237-billion-euro deal remained at immediate risk, pointing to the need to get a large commitment from private holders of Greek bonds to participate in the debt writedown.
The Fund has still to decide its own level of participation in the $110 billion euros of official aid being offered in the rescue package, the official said.
The IMF's role is crucial to ensuring that both the private sector and Greece's eurozone partners contribute to a joint effort.
Greece, mired in recession for five years and with unemployment above 20 percent and rising, has had to revise up its public deficit targets meanwhile.
In its draft law on additional austerity measures, the government raised Wednesday its 2012 deficit forecast to 6.7 percent of gross domestic product from a prior estimate of 5.4 percent of GDP.
The parliamentary vote on Thursday came a day after Greek unions staged another protest in the capital and Greece's second city Thessaloniki against austerity measures.
They include a 22 percent cut in the minimum wage and 12 percent cuts in pensions of more than 1,300 euros, further adding to the economic hardship of ordinary Greeks.
Prime Minister Lucas Papademos said reforms would restore economic growth while Finance Minister Evangelos Venizelos pressed lawmakers to pass the legislation as debt deadlines loomed.
Venizelos said an official offer to private creditors must be made by Friday so a debt swap could be concluded by March 12 for bonds governed by Greek law.
Otherwise, "Greece will face a problem with its reserves on March 14" when it must repay debt of nearly 14.5 billion euros, the finance minister warned.
Next on the parliament's agenda is a debate on 3.2 billion euros ($4.2-billion) in spending cuts crucial to the bailout deal, that should be approved by next Tuesday the latest.
The measures must be approved before elections expected in April which pollsters say could fail to produce a clear majority, clouding prospects for implementation of the debt accord.
Copyright AFP (Agence France-Presse), 2012