ATHENS - The Greek parliament approved the 2015 state budget early Monday with a fresh government plea for national consensus to strengthen the country's position in negotiations with international creditors over the transitional period to the post-bailout era.

The draft budget was approved with the backing of the deputies of the conservative-led ruling coalition, which accounts for more than half of the parliament seats.

The government budget foresees a 2.9-percent increase of the Greek gross domestic product (GDP) in 2015, up from 0.6 percent this year.

However, the troika of international lenders -- the European Union (EU), the International Monetary Fund (IMF) and the European Central Bank -- point more conservative estimates which see a less-satisfying 2 percent of GDP primary surplus in 2015 and a 2-billion-euro (about 2.46 billion U.S. dollars) budget gap.

The Greek government tabled the draft budget without a prior agreement with lenders on the size of next year's fiscal gap and the needed policies to cover it.

Addressing the assembly ahead of the vote, Prime Minister Antonis Samaras dismissed the opposition's criticism that the government's draft was not realistic and that soon Athens will be forced to introduce more austerity measures under the lenders' pressure.

"We have proved so far in previous years that our estimates were more accurate. (The) troika is conservative and SYRIZA is entirely wrong," Samaras said.

Samaras accused SYRIZA, the radical left opposition party, of undermining the country's exit from the memorandum of understanding, a multi-billion-euro rescue plan signed between the government and the troika in 2010.

After implementing austerity and reform programs designed in cooperation with international lenders, Greece is expected to return to growth this year.

The prime minister said the government firmly rejects the troika's suggestions for supplementary measures worth 1.7 billion euros (about 2.09 billion dollars), because they are not necessary to meet the targets.

Finance Minister Gikas Hardouvelis also said the government's prediction was correct and the budget would be implemented as planned.

Hardouvelis said the painful structural reforms promoted by the government are the only way to support growth regardless of bailout programs and creditors' requests and therefore the opposition should embrace them.

Both Samaras and Hardouvelis appeared confident that a deal with the EU and IMF auditors on the final review of Greece's bailout program will be clinched soon.

For his part, SYRIZA leader Alexis Tsipras talked about a "catastrophic" economic planning which will prolong the suffering of the Greek society, repeating his party's demand for early general elections.

SYRIZA, which sees opportunities in the upcoming presidential election scheduled for February, has been pushing for months for snap elections.

Under the Greek Constitution, the parliament votes to elect a new president, which requires a majority of at least 180 votes in the 300-member assembly.

The coalition of the New Democracy party of Samaras with the socialists holds just a slim majority and therefore needs the support of opposition parties and independent MPs. If they fail to get it, the country will head to early national elections within weeks, which will increase concerns over a new circle of political uncertainty.

Surveys show that the majority of respondents say they do not want snap general elections.