By Erik Kirschbaum
BERLIN (Reuters) - Chancellor Angela Merkel's conservatives climbed to their highest level in more than three years in a leading opinion poll published on Friday, but the results pointed to no outright winner emerging from next September's election.
The closely watched Politbarometer for ZDF TV indicated neither Merkel's center-right coalition nor a center-left alliance would be able to win a majority.
The ZDF poll also showed a 48 to 44 percent majority of Germans now believe Greece should remain in the euro zone, up two points from the previous poll. Earlier polls showed a large majority in favor of Greece leaving the euro zone.
Merkel, who has in general been praised in Germany for her leadership in the euro zone crisis, has campaigned more vocally on behalf of Greece staying in the euro zone in recent weeks.
Merkel's Christian Democrats and the Bavarian sister party, the Christian Social Union (CSU), rose 1 percentage point to 39 percent in the ZDF Politbarometer poll - their highest level since 40 percent in September 2009 just before the last election when they won 33.8 percent.
But support for her Free Democrat (FDP) coalition partners remained stuck at 4 percent, one point short of the 5 percent threshold needed for seats in parliament. The FDP won 14.6 percent in the 2009 election.
The main center-left opposition Social Democrats (SPD) fell 2 points to 29 percent in the ZDF poll while the Greens, the SPD's preferred coalition partners, rose 1 point to 13 percent. With 42 percent the two parties would fall short of a majority.
The SPD had jumped to six-year highs in early October after naming former Finance Minister Peer Steinbrueck as their candidate to run against Merkel next year. In an October 10 Forsa poll, the SPD climbed to 30 percent.
The Left party were unchanged at 6 percent, the ZDF poll showed. It also found that the Pirates party would win only win 4 percent, down 1 point from the last poll.
The Pirates - self-confessed nerds campaigning on an eclectic platform of free Internet downloads, data protection, free underground rounds and legalizing drugs - had surged into double digits earlier this year, reaching as high as 13 percent.
But they have dropped in polls as doubts about their seriousness and ability to come up with constructive solutions grew. The Pirates are also wracked by in-fighting. Two party leaders announced their resignations on Friday: executive board members Julia Schramm and Matthias Schrade.
The poll results would mean only four parties would be in the next parliament with the FDP and Pirates falling short.
That would mean Merkel's CDU/CSU could form another "grand coalition" with the SPD, the same constellation that ruled from 2005 to 2009, or a new coalition with the Greens, which has so far only been tried in one state, Hamburg.
Political analysts, and Greens leaders, believe it would be difficult if not impossible to bridge some of the wide gaps between the conservatives and the pro-environment Greens.
The SPD and Greens could in theory form a coalition with the Left party, but many SPD leaders on the party's centrist wing are opposed to that. Many SPD leaders also are against a repeat of being junior coalition partners in a grand coalition.
(Editing by Jon Hemming)