By Jan Schwartz
HAMBURG (Reuters) - Germans voted in Hamburg state elections on Sunday and are likely to inflict a bruising defeat on Chancellor Angela Merkel's Christian Democrats, making it harder for her federal coalition to pass laws.
Hamburg is the first electoral test for Merkel this year, and the opposition Social Democrats (SPD), riding high in opinion polls, are hoping for a big win to give the centre-left a burst of momentum before six further state elections in 2011.
By early afternoon turnout was slightly higher than at the same time during the last vote in the northern port, Germany's second-largest city. Opinion polls have signalled a big SPD win and first exit polls are expected after polling stations close at 6 pm (1700 GMT).
Defeat in Hamburg would make life harder for Merkel's centre-right government as it would give the opposition firm control of the Bundesrat, or upper house of parliament, which represents Germany's states.
It has to approve about half of the legislation that passes through the Bundestag lower house.
Hamburg will also send a signal to voters before the other state votes, especially in the southwestern region of Baden-Wuerttemberg where Merkel's CDU is in danger of losing power in March.
Merkel's party, which has been recovering nationally from a plunge in popularity last year, is facing fresh setbacks. Popular Defence Minister Karl-Theodor zu Guttenberg has been embroiled in a plagiarism scandal over his doctoral thesis, allegations he has dismissed.
Bundesbank chief Axel Weber, who was seen as a key contender for the top job at the European Central Bank, said he would quit at the German central bank, a decision that popular media have interpreted as a blow to Merkel.
Opinion polls in Hamburg show the SPD projected to win about 46 percent of the vote. The CDU, which took 42.6 percent in the last election in 2008, has plunged to 25 percent.
"I am optimistic. Many citizens have told me in the past few days that they've already voted for me... or will do so on Sunday," said SPD candidate and former Labour Minister Olaf Scholz as he made his vote.
The SPD hopes to win an outright majority in Hamburg. But it may need to form a coalition with the Greens, who are polling around 14 percent. The Left party are at 6 percent and the liberal Free Democrats at 5 percent.
Hamburg, long a left-wing bastion, was ruled by the SPD for 44 years before it lost power to Merkel's CDU 10 years ago. The SPD's candidate Scholz, 52, has purged the party of corrupt officials who cost it control of Germany's second city.
Analysts believe the SPD nationally might get a short-term boost with a second consecutive state election victory following their win in North Rhine-Westphalia last May. But it is unlikely that losing Hamburg would have a lasting impact on Merkel's party.
The CDU plunged in Hamburg polls after its leader Christoph Ahlhaus, a colourless lawyer, took over from once-popular CDU mayor Ole von Beust, who abruptly quit in July. A CDU coalition with the Greens failed in November, prompting the elections.
Nationally, Merkel's conservatives are at about 36 percent. The SPD (22 percent) and their preferred partners, the Greens (20 percent), are just ahead of the ruling coalition of Merkel's conservatives and their FDP partners (5 percent) combined.
(Writing by Erik Kirschbaum and Annika Breidthardt; editing by David Stamp)
