Merkel party support dives in key German state - poll

German Chancellor Angela Merkel poses for photographers after the television recording of her summer interview in front of the Reichstag, the seat of the German lower house of parliament Bundestag, in Berlin, August 29, 2010.

BERLIN (Reuters) - Chancellor Angela Merkel's Christian Democrats are in danger of losing control of a conservative southern German state they have governed since 1953, an opinion poll published on Wednesday said.

A Forsa poll in Stern magazine showed support for Merkel's CDU-led centre-right coalition with the Free Democrats in Baden-Wuerttemberg fell to 43 percent while the opposition Social Democrats (SPD) and Greens scored 48 percent.

The next Baden-Wuertemberg election is due in March 2011. Losing control of the conservative bastion would be a severe setback for Merkel, whose centre-right coalition at the federal level has also seen support plunge since taking power in 2009.

Merkel's coalition lost control of the upper house of parliament, the Bundesrat, in July when the SPD took back the most populous state, North Rhine-Westphalia. That has forced her to make compromises with the opposition on some laws.

CDU popularity has been hurt also by one of Germany's biggest-ever building projects -- a new 4.1 billion euro ($5 billion) train station in Stuttgart -- at a time when many Germans are feeling the squeeze of budget austerity.

Nearly 30 percent of the voters in Baden-Wuerttemberg -- whose economy is as large as Poland's -- said the Stuttgart station would be the decisive factor in their voting decision.

Protests against the station have turned violent in the last week after demolition work began and what was a one-issue protest has become a wider outcry against politics in general.

The Forsa poll found 51 percent in Baden-Wuerttemberg are against the station, 26 percent in favour and 23 percent undecided.

Demonstrators and riot police have scuffled during protests and seven demonstrators were forcibly pulled off the station roof last week by elite police squads. Numbers have grown from a few thousand to tens of thousands.

The Stern/Forsa poll said CDU support fell to 37 percent compared with 44.2 percent won in the last election in 2006. Their FDP partners were down to six percent compared with 10.7 percent in 2006.

The opposition SPD and Greens would each win 24 percent, the poll of 1,068 voters between August 16 and 27 by Forsa found.

In 2005, then chancellor Gerhard Schroeder called for snap elections after his SPD lost control of another major state they had held for decades, North Rhine-Westphalia. Schroeder's SPD-Greens government was ousted four months later.

(Editing by Louise Ireland)