The election will be the first since the debt crisis exploded at the end of 2009, dragging the country into its worst economic recession since World War II, pushing unemployment to record highs and shaking the euro.
The conservative New Democracy and the Socialist PASOK, which back the interim government of technocrat Prime Minister Lucas Papademos, have suffered in opinion polls for supporting the bailout plan and may not gather enough votes to rule.
Polls show small parties opposing the steep wage and pension cuts imposed by the EU and the IMF in return for aid are gaining ground and may stop the leading parties from even forming a coalition government.
Papademos was expected Wednesday afternoon to formally ask President Karolos Papoulias to dissolve parliament and hold elections on 6 May.
Officials have been saying for days that voters would go to the polls on the first Sunday of May, after Papademos' emergency government completed its mandate by clinching a new EU/IMF rescue deal and a landmark debt restructuring.
"Elections, it now seems, will take place on May 6," Health Minister Andreas Loverdos told parliament.
Party leaders have already unofficially started the campaign, with conservative leader Antonis Samaras telling supporters over the weekend that he would boost low pensions and create jobs.
Recent opinion polls show his party would gather between 18% and 25% of the vote, ahead of PASOK's 11%-16% but far behind the socialists' sweeping 43.9% win in the pre-crisis election in October 2009.
Samaras has said repeatedly, however, that he is aiming for a full majority and has warned that he might trigger a repeat election if he does not get enough votes.
"I am entering the field, just as all big teams do, to win. Not to get a tie, not to lose," he told Mega TV on Monday. "And if a government cannot be formed ... we will have to go again to elections."
Some surveys cast doubt on whether the only two parties that back the bailout can gather enough votes to renew their coalition, although this is still considered the most likely outcome.
Both New Democracy and PASOK back EU/IMF reforms such as opening up of closed professions, slashing a fifth of the public sector workforce and cutting pensions, but Samaras said he would renegotiate some parts of the plan.
Whoever wins the election will have to agree additional spending cuts of 5.5% of GDP - or about €11 billion - for 2013-2014 and gather about another €3 billion from better tax collection to keep getting aid, the IMF has said.
The Fund has warned the election is posing a political risk, casting doubt on the implementation of agreed policies. Parliament approved on Monday a grant of nearly €30 million to fund its cash-strapped political parties, in a vote that split lawmakers and triggered some criticism in the recession-hit country and abroad.