BERLIN (Reuters) - Chancellor Angela Merkel’s Bavarian allies are losing support ahead of an Oct. 14 state vote that will likely force them into coalition to form Germany’s most influential regional government and complicate governing in Berlin, a poll showed on Thursday.

FILE PHOTO: German Chancellor Angela Merkel and Interior Minister Horst Seehofer take part in a conference about the equal living conditions between urban and rural areas in Berlin, Germany September 26, 2018. REUTERS/Hannibach Hanschke

The falling support for the Christian Social Union (CSU) suggests the party will lose the absolute majority with which it has ruled Bavaria for most of the post-war period, a development that risks grave implications for Merkel’s government in Berlin.

The Infratest dimap poll for broadcaster ARD showed support for the CSU falling two points to 33 percent. Such a result would compare with the 47.7 percent the CSU scored in the last state vote in 2013 and see the party lose its absolute majority.

The CSU has fallen short of an absolute majority in Bavaria’s state assembly only once since 1954, when it missed by two seats in 2008. Its vote share, usually close to 50 percent, has not fallen below 43 percent in 64 years.

That regional power has assured Bavarian CSU leaders a solid grip on senior cabinet positions in the conservative national governments that have dominated post-war Germany.

If the latest poll is right, the vote will be a heavy blow to CSU leader Horst Seehofer, who props up Merkel’s coalition government in Berlin and serves as interior minister. If he is weakened, Seehofer could become more prickly - or even quit.

Seehofer was at the center of a crisis over the fate of Germany’s spy chief last month that came close to tearing apart Merkel’s ruling coalition, an awkward alliance of her conservative Christian Democratic Union (CDU), the CSU and the left-leaning Social Democratic Party (SPD).

The Infratest dimap poll showed support for the ecologist Greens up one point at 18 percent, which would make them the second largest party in Bavaria.

Support for the SPD was unchanged at 11 percent and the right-wing Alternative for Germany (AfD) was also steady, at 10 percent, an outcome that would see the anti-immigration party muscle into Bavaria’s regional parliament for the first time.

Infratest dimap polled 1,002 Bavarian voters on Monday and Tuesday. The poll showed that 71 percent of those surveyed thought Bavaria would be better off with a coalition government.