Germany's political class was facing a tense night Sunday, with early indications showing Germans heading to the polls for national parliamentary elections in greater numbers than in 2009, dpa reported.
Opinion polls suggest Chancellor Angela Merkel's current ruling coalition may lose its parliamentary majority, amid speculation that her junior partner, the Free Democratic Party (FDP), might not pull together sufficient votes to re-enter the parliament, or Bundestag.
Merkel, leader of the centre-right Christian Democrats (CDU), is still expected to remain chancellor for a third term.
However, the fracturing of her current coalition means she may have to start looking for other partners.
That might not be an easy feat. Although Merkel's first term as chancellor, from 2005 to 2009, was in a grand coalition with Germany's other large party, the centre-left Social Democrats (SPD), the SPD has not yet said if it would consider re-entering such an alliance.
Merkel cast her vote Sunday in Germany's general election after walking from her city apartment to a polling station at the city's Humboldt University campus.
Television crews filmed the CDU leader, wearing one of her trademark jackets, as she dropped her vote in the ballot box.
Peer Steinbrueck, the SPD candidate to replace Merkel, voted in Bonn, telling reporters he had slept well and that he had enjoyed the election.
Steinbrueck underlined his vow not to serve under her as a cabinet minister, the newspaper Bild am Sonntag reported Sunday.
Pre-elections polls indicate the SPD will come a distant second to Merkel's Christian Democrats, with between 26 and 28 per cent of the vote. Some supporters have voiced regret at his personal refusal to join a dream-team government of the two biggest parties.
"For me, two things stand out. I want to be chancellor of a Social Democratic and Greens government. And I am not available to serve in the cabinet of a grand coalition," he said, just hours before the German general election got under way Sunday.