Greece appears headed for a new clash with Germany over its rigid bailout program as the winners of Sunday's Greek election prepare to ask Europe for more time to cut public spending.

Greece's conservative New Democracy party and its likely Socialist coalition partner, known as Pasok, are working on a proposal to ask other euro-zone countries for an extra two years to meet Greece's fiscal targets, officials involved in the preparations said. The request would mean that on top of the €173 billion ($218.7 billion) bailout plan agreed early this year, Greece would need an additional €16 billion in financing from Europe, these officials said.

The plan would present Northern Europe's creditor nations, led by Germany, with a dilemma. Europe is eager to help a new Greek government to strengthen popular support for the country's tough bailout program and to combat Greece's deepening recession. But German Chancellor Angela Merkel is also loath to increase the size of the Greek bailout, something that could split her fractious governing coalition in Berlin.

Ms. Merkel told a news conferences during the summit of the Group of 20 leading industrial and developing economies in Los Cabos, Mexico, that Greece's leaders "must fulfill their commitments quickly" under the bailout deal.

"There won't be any changes to the memorandum of understanding" setting out the fiscal and other overhauls that Athens must make in return for aid, she said.