The international ratings agency Fitch said an electoral victory by a Greek party that negotiated terms of a financial bailout would ease ratings pressure on euro zone partners.
A narrow victory by the New Democracy party has reduced the risk of a Greek debt default and possible euro zone exit.
Fitch said it would take that into account as it assesses the creditworthiness of the 17-nation bloc.
"Fitch will not place all euro zone sovereigns on Rating Watch Negative as it had indicated would be the case if a Greek euro exit were a probable near-term event," a statement said.
"Fitch will not place all euro zone sovereigns on Rating Watch Negative as it had indicated would be the case if a Greek euro exit were a probable near-term event," a statement said.
In Athens, Greek politicians worked to form a viable coalition after parties that essentially backed the terms of an euro zone bailout won enough support on Sunday to envisage setting up a new government.
Fitch added however that "while the risks from Greece have fallen for now, the severity of the systemic crisis engulfing the euro zone is unlikely to diminish until European leaders articulate a credible road-map that would complete monetary union with much greater fiscal and financial integration.
"Downward pressure on the sovereign credit profile and ratings of eurozone sovereign governments will intensify so long as a credible path to closer union and a more coherent and united policy response are absent," the agency warned.
World powers relieved by Greek vote
World powers breathed a sigh of relief today after pro-bailout parties won Greece's election but warned there was no time to lose to form a government committed to austerity measures.
The likely emergence of a left-right coalition has eased fears that Athens will exit the euro zone.
This prospect was applauded by heads of government and finance chiefs who said it was vital that Greece stay on board.
The European Union meanwhile pledged support to the next Greek government.It said the conservative New Democracy party and its likely coalition partner, the socialist Pasok party, should urgently form a new administration.
"We are hopeful that the election results will allow a government to be formed quickly," said the presidents of the European Council and the chairman of the European Commission, Herman Van Rompuy and Jose Manuel Barroso.
"We will continue to stand by Greece as a member of the EU family and of the euro area," they added, in a statement issued in the Mexican town of Los Cabos on the eve of the G20 summit of the world's leading economic powers.
In the US, White House spokesman Jay Carney said President Barack Obama believed that it was "in all our interests for Greece to remain in the euro area while respecting its commitment to reform".
The International Monetary Fund indicated that it would now set about a renegotiation of Greece's €130 billion bailout programme although Germany warned that there could be no fundamental rewrite.
"We stand ready to engage with the new government on the way forward to help Greece achieve its objective of restoring financial stability, economic growth and jobs," said an IMF statement.
The IMF is pressing for urgent talks with Greece in the coming days and the Eurogroup of European finance ministers in Brussels has urged parties to move "rapidly" to set up a new government that would implement key reforms.
German Chancellor Angela Merkel was one of the first to congratulate Antonis Samaras after his New Democracy party won on Sunday, saying she was confident Athens would abide by its pledges to cut spending in return for bailout funds.
"She stated that she would work on the basis that Greece will meet its European commitments," said a government statement recounting her phone conversation with Samaras.
German Foreign Minister Guido Westerwelle said he was "relieved" by the election result but he ruled out any changes to international reform demands in return for bailouts.
"I am very relieved by the results of the Greek elections. It's a vote for Europe," Westerwelle told reporters in Berlin. "What's imperative is that a government is quickly formed that is capable of acting - it's about more than fiscal discipline, it's about growth and competitiveness. The result of the Greek elections is that there are no concessions because what has been agreed is now what we will implement. There can be no substantial changes to the agreement,'' he added.
Asian markets were first to react to the election, all registering rises after the prospect of a Greek euro exit receded. But the governments in Tokyo and Beijing highlighted the continuing sense of scepticism that a corner really had been turned.
"We will be paying close attention to upcoming negotiations to form a coalition," chief Cabinet Secretary Osamu Fujimura, the Japanese government's top spokesman, told reporters.
"Our country hopes that a stable government will be launched early and make progress towards stabilising markets. We hope that European countries will urgently take measures to strengthen its financial sector," he added.
Chinese foreign ministry spokesman Hong Lei told reporters that Beijing was "always supportive of the EU and the eurozone's efforts" to resolve its crisis. "We respect the choice of the Greek people. We hope the election result can help stabilise the economy in the euro zone," he said.
But Australia's finance minister was more blunt as he hit out at Europe for failing to adequately tackle financial turmoil.
"It is important that Greece's political parties quickly undertake coalition discussions and form a stable government," Wayne Swan told parliament. "I accept that there will be continuing volatility from Europe for some time yet, but I do not accept that the pace and scale of action to address it has been adequate," he added.
Tánaiste Eamon Gilmore said the outcome of the Greek election will add stability to the euro zone. He said that as the political uncertainty is coming to an end, there will be a government the European institutions can deal with.
