Greek unions, the unemployed and communists will protest on Wednesday against spending cuts introduced to secure a multi-billion-euro bailout, and lawmakers will debate a debt swap to avoid imminent bankruptcy.
Motorcycle groups and striking journalists are also expected to converge on the capital's central Syntagma square in front of parliament at 4 p.m. (1400 GMT) to protest against the cuts, vital to securing the new 130 billion euro ($172 billion) rescue package but certain to prolong a deep recession in Greece.
Euro zone finance ministers approved the rescue deal on Tuesday after forcing Greece to make cuts and commit to reforms to make the economy more competitive and by agreeing private bondholders would have to take larger losses.
The Greek parliament will debate a bill, called Collective Action Clauses (CACs), that will force all investors to accept the debt swap once a threshold of two-thirds participation in the transaction is reached.
The debt swap, in which private investors swap their bonds for lower-value debt, is a vital part of the rescue plan aimed at cutting Greece's liabilities from 160 percent of gross domestic product to 120.5 percent by 2020, according to the terms of the deal.
Greece's technocrat prime minister, Lucas Papademos, said on Tuesday the swap had to be completed by March 10 at the latest, 10 days before 14.5 billion euros in debt repayments fall due.
Police placed metal barriers in front of the national assembly to try to prevent a repeat of riots on February 12 when hooded youths torched and looted buildings across central Athens as lawmakers adopted more than 3 billion euros in cuts to wages, jobs and pensions - the price of the bailout.
The complex deal reached on Tuesday buys time to stabilize the 17-nation currency bloc and strengthen its financial protection against a Greek default, but it leaves deep doubts about Greece's ability to avoid difficulties in the longer term.
It has also angered Greeks by calling for the deployment of a permanent team of foreign inspectors to make sure Athens sticks to the terms of the new bailout, the country's second in less than two years.
The plan reflects the mistrust between Greece and foreign lenders - in particular EU paymaster Germany - after years of backsliding by Athens, but it has riled Greeks whose sense of national pride has been hurt by the threat of bankruptcy.
In an editorial on Wednesday, the conservative daily Eleftheros Typos said default had been avoided for now.
But the bailout will fail, it said, as long as the policy of extreme austerity - which has led the country into a vicious circle of recession, driven unemployment to unprecedented levels, cut dramatically the income of workers and pensioners and killed the market - continues.
Parliament must also adopt more than 3 billion euros in budget savings for 2012, already endorsed in principle by lawmakers this month.
The cuts have driven Greece deeper into a recession now in its fifth year, driving unemployment up to almost 21 percent and fuelling unrest. ($1 = 0.7539 euros)
(Additional reporting by Harry Papachristou; Writing by Matt Robinson; editing by Elizabeth Piper)