BERLIN (Reuters) - German Chancellor Angela Merkel's conservatives have climbed to their highest opinion poll level in nearly seven years but will not be able to continue their centre-right coalition with the slumping Free Democrats (FDP), a survey said on Wednesday.
The Forsa poll published on Wednesday, nine months before an election, found Merkel's Christian Democrats and their Bavarian sister party, the Christian Social Union (CSU) rising three points to 41 percent, the highest since March 2006.
But her FDP coalition allies fell one point to four percent in the weekly poll for RTL TV and Stern magazine and would fall below the five percent threshold needed for seats in parliament. Merkel is seeking a third term in September's election.
The centre-left opposition Social Democrats (SPD) and their Greens allies were down one point to a combined 40 percent. The SPD were steady at 27 percent while the Greens fell one point to 13 percent. The Left party were steady at eight percent.
Neither Merkel's centre-right coalition nor the centre-left would win a majority if those were the election results.
Political analysts believe the most likely outcome of next September's election would be a grand coalition of conservatives and the SPD, the right-left alliance that led Germany from 2005 to 2009. A conservative-Greens coalition is also a possibility.
German voters are in general pleased with the way Merkel's centre-right government has led the country through the euro zone debt crisis, the country's most pressing issue.
The economy is in relatively good shape thanks to strong export industries and the government expects the economy to continue expanding in 2013. Unemployment has held steady near two-decade lows of 6.9 percent.
Germany's economy powered through the first two years of the euro zone's sovereign debt crisis, posting 4.2 percent growth in 2010 and 3 percent last year before slowing to about 0.8 percent in 2012, while some peers were grinding to a halt.
Merkel's CDU put on a show of unity at their annual party congress three weeks ago, re-electing her as the party leader by a record margin of 97.9 percent. It was her best score since taking over the CDU leadership 12 years ago.
Merkel's CDU is nevertheless facing a tough state election battle on January 20 in Lower Saxony, where the popular CDU incumbent David McAllister could be ousted even though the CDU is polling around 40 percent in the northern state.
The CDU-FDP coalition could be defeated if the FDP fails to win seats. They are polling around 4 percent in Lower Saxony.
The Forsa poll showing Merkel's conservatives at 41 percent confirms other polls showing solid support for her party. An Emnid poll in Bild am Sonntag newspaper on Sunday found the CDU/CSU steady at 40 percent for the last three weeks while the FDP were at four percent compared to 41 percent for the centre-left alliance of SPD (28 percent) and Greens (13 percent).
(Reporting By Erik Kirschbaum; Editing by Angus MacSwan)