Bavaria's Christian Social Union (CSU) lost its decades-old absolute majority on Sunday as voters defected to smaller parties in a state election seen as a test of support ahead of national polls next year, dpa reported.
Computer projections showed a swing of more than 17 percentage points away from the sister party of Chancellor Angela Merkel's Christian Democrats (CDU), forcing it to look for a coalition partner.
The CSU polled 43.4 per cent of the vote in its worst showing in half a century. The centre-left Social Democrats (SPD), which governs in a grand coalition with Merkel's party in Berlin, polled 18.6 per cent, a decline of 1 percentage point from the last state election in 2003.
Analysts said the outcome could both increase tension between the federal coalition partners and hurt Merkel's chances of retaining power in federal elections expected in September 2009.
CSU Secretary General Christine Haderthauer said the disastrous result was a black day for the party, which had ruled unchallenged for more than 40 years.
In the last state elections in 2003, the CSU polled 60.7 per cent of the vote in the strongly Catholic state, where some of Germany's leading companies have their headquarters, including Siemens and BMW.
The party's stated intent had been to retain its absolute majority in the 180-seat Parliament in Munich. "We have clearly failed to achieve our goal," Haderthauer said.
Prime Minister Guenther Beckstein, who was elected last year after longtime leader Edmund Stoiber was toppled in a party revolt, ruled out stepping down to take responsibility for the poor showing.
"The people have shown that they want a CSU-led government, but that they do not want the CSU to govern Bavaria alone," he said, adding that the party would immediately start to look for a coalition partner.
The most likely contenders are the liberal Free Democrats (FDP), who polled 8 per cent of the vote to enter Parliament after an absence of 14 years.
Another possibility is the Free Voters, a conservative party that will make its parliamentary debut after winning 10.2 per cent on a platform seeking greater local power.
The environmentalist Greens won 9.4 per cent, but the pro-labour Left Party at 4.3 per cent failed to clear the 5 per cent hurdle needed to get into Parliament.
The CSU's good showing in Bavaria in the 2004 general election helped elevate Merkel to power, but its popularity has been steadily eroding under Beckstein and party Chairman Erwin Huber.
Losses by the state-owned bank BayernLB, the scrapping of a prestigious super-fast train link to the Munich airport and a controversial smoking ban combined to fuel voter discontent.
Analysts said the party's poor performance could increase pressure on the CSU leadership, which had been criticized for running a tepid campaign and failing to galvanize voters.
The party ran a campaign highlighting the CSU's past successes while pushing for greater tax breaks for commuters and better conditions for working mothers.
Beckstein committed a major gaffe during the election campaign when he said it was alright to drive after consuming two litres of beer at the world-famous annual Oktoberfest, currently taking place in Munich.
The remarks caused an outcry, and the premier was forced to clarify them a few days later, saying that driving would still be possible if two litres of beer were consumed over several hours.