BERLIN (Reuters) - Support for Chancellor Angela Merkel's conservative bloc has slumped to a new low, and the far-right Alternative for Germany (AfD) would be the second-biggest party if an election were held right away, a poll showed on Friday.
The ARD DeutschlandTrend survey put support for Merkel's conservative alliance - her Christian Democratic Union (CDU) and its Bavarian allies, the Christian Social Union (CSU) - at 28 percent, down one point from Sept. 6 and at a record low.
Merkel, who has led Germany since 2005, only narrowly averted the collapse of her coalition government in June after a row between the CDU and the CSU over immigration policy.
The conservative sister parties and their Social Democrat junior coalition partners agreed to oust the head of the BfV domestic agency over accusations that he harboured sympathies to the far-right.
But the decision to give Hans-Georg Maassen a deputy minister position at the interior ministry was derided as a bad compromise that allowed the ruling parties to paper over deep differences that make their coalition unworkable.
The anti-immigration AfD, which has backed Maassen and said his removal would threaten national security, gained two points in the ARD DeutschlandTrend survey, conducted by pollster Infratest Dimap, to a record high of 18 percent.
This made it the second-largest party, ahead of the SPD, which fell to 17 percent.
A separate survey from INSA showed that almost half of Germans were in favour of a new election, reflecting discontent with the handling of the Maassen affair that has eroded Merkel's authority. Almost a third were against a new vote.
In last September's federal election, the CDU/CSU bloc won 32.9 percent of the vote and the AfD surged into the national parliament for the first time with 12.6 percent, making it the third-largest party. The SPD came second with 20.5 percent.
Infratest Dimap polled 1,035 voters across Germany from Monday to Wednesday of this week.
(Reporting by Maria Sheahan; Editing by Hugh Lawson)