|Exit polls reveal Merkel's Christian Democrats came in second to the Social Democrats [Reuters]
Angela Merkel's conservative Christian Democrats (CDU) have been beaten by the centre-left Social Democrats (SPD) in a regional election in the city-state of Berlin, according to exit polls aired on German television.
The figures aired on ARD television showed the German chancellor's party had polled 23.5 per cent of the vote, with the SPD on 29.5 per cent and the Greens on 18 per cent.
The defeat would mark the CDU's sixth defeat in seven state elections held this year.
Although the CDU was up from 21.3 per cent compared to the last poll in 2006, it is well below the 40 per cent vote the party used to secure in the capital through the 1980s and 1990s.
Although Mayor Klaus Wowereit is returning to his seat, he will have to build a new coalition in Berlin, after a weak showing by his previous partner, the Left party, who polled 11.5 per cent.
In more bad news for Merkel, her coalition partner, the Free Democrats (FDP), failed to poll the five per cent threshold needed to win a single seat accroding to the exit poll.
"Everyody was expecting a devastating blow, but it was not against the CDU, it came against the junior partner of her coalition, who polled just 1.5 per cent," said Al Jazeera's Nick Spicer in Berlin.
"People here are calling it a debacle, they are being wiped off the political landscape, and people are asking if they [the FDP] deserve their position in the governing coalition."
The technology-friendly Pirate Party made its debut in a German legislature, capturing 8.9 per cent of the vote.
Formed in 2006, the party was able to win widespread support from young Berliners.
It has expanded its platform from its original push from file sharing and data protection on the internet to include education and citizens rights.
"They [the Pirate party] even went to the regional airport in their underwear and bikinis to protest because they were unhappy with the security procedures there," said our correspondent.
"They are now represented in the state legislature."
Spicer said the election's main issues have been Berlin's unemployment - which, at 13 per cent, is double the national average - and the rising cost of rental accommodation.
The FDP defeat could build pressure on the party - which has plunged from record popularity of 14.6 per cent in the 2009 federal election - to remove Guido Westerwelle, the unpopular foreign minister.
Meanwhile, Merkel, who has been criticised for her leadership during the eurozone crisis, is halfway through a four-year term as the country's head of government.
The defeats for her CDU have battered her popularity ahead of a critical vote in the Bundestag at the end of September to give the European Financial Stability Fund, the eurozone bailout fund, more powers.
The SPD, in opposition at the national level since 2009, want to use the result in Berlin - Germany's largest city with 3.4 million people - to build momentum to oust Merkel in the next federal election in 2013.
The SPD has ousted or helped defeat the CDU in Hamburg and Baden-Wuerttemberg this year and remained in power elsewhere.