A meeting of Greek political leaders at which the final details of a new interim government were expected to be confirmed has been pushed back to Thursday.
The announcement of the delay came hours after George Papandreou, the outgoing Greek prime minister, said that the country's main parties had reached an agreement on forming a unity government tasked with tackling the country's debt crisis.
Antonis Samaras, the opposition leader, blamed Papandreou's governing Socialists for the delay after three days of talks, saying the constitution demanded the ruling party take the initiative in naming a candidate to head a new government.
In an apparent farewell address on national television, an emotional Papandreou said: "We have agreed on someone who will unite us."
"I would like to wish every success to the new prime minister and of course the new government. I will stand by them
and I will support them with all my strength."
He also stressed that his country would do whatever necessary to stay in the eurozone.
Earlier, reports suggested that Philippos Petsalnikos, the speaker of the Greek parliament, had emerged as the probable new prime minister.
Petsalnikos, who has led the parliament since 2009, was first elected as a Socialist deputy in 1985.
But a member of Papandreou's cabinet told the Reuters news agency that Petsalnikos' nomination had provoked opposition among some who saw him as too close to the outgoing prime minister.
"This whole affair does not do us much honour," he said. "There are moves by MPs in both major parties to sign a joint letter against Petsalnikos."
Others called for the appointment of a technocratic government led by Lucas Papademos, a former vice-president of the European Central Bank and head of Greece's central bank.
"The only solution is Papademos. If he accepts by tomorrow morning we will be able to form a strong government that will pull the country out of the crisis," Spyros Vougias, a Socialist deputy, told Reuters.
The new cabinet faces the challenge of balancing access to international bailout funds necessary to keep the country from defaulting on its debts - notably a new $137bn (100bn euros) European Union rescue package - with the grievances of a population already feeling the pain of several rounds of tough austerity cuts.
Difficult task ahead
A demand from eurozone leaders for a signed commitment to the terms of the latest bailout deal agreed to less than two weeks ago has been holding up the official announcement, Al Jazeera's Andrew Simmons said.
Papandreou's office said earlier on Wednesday that the prime minister had spoken by telephone with French President Nicolas Sarkozy on Wednesday morning and discussed "the developments in Europe and the eurozone," as well as the power-sharing negotiations in Athens.
Papandreou informed Sarkozy "of the imminent [formation] of a new government in Greece supported by the majority and the opposition," the French president's office said.
John Psarapoulous, an Athens-based political commentator, told Al Jazeera on Wednesday that both of Greece's main parties were committed to forming a government.
"At this point, both parties have committed themselves ... to doing it. Greece would now fall apart very badly if they were to [fail], and the European Union might very well withdraw even the latest offer of help from October 27. At this point Greece is being asked if it wants to stay in the euro, so this national unity government is about achieving that," he said.
The EU bailout deal finalised last month would give Greece $137bn (100bn euros) in loans and a further $137bn in debt reduction and $41.3bn in government guarantees. Banks have agreed to accept losses on their Greek bond holdings.
The package is designed to ease the country's debt burden by nearly a third, but the government would be required to make further cost cuts.
Earlier rounds of cuts over the past two years have prompted Greek citizens to take to the streets in violent protests.
Regardless of the outcome of talks, our correspondent said that in the short-term any new Greek government would be unlikely to take a radically different approach to dealing with the crisis.
"The basic premise to this whole new government is to satisfy the eurozone leaders and try and put some more expertise, some more political consensus in the way that Greece goes about its business," Simmons said.
Source: Al Jazeera and agencies