German chancellor Angela Merkel delivers a speech during a financial conference at the stock exchange in Frankfurt, Germany, September 4, 2018. REUTERS/Kai Pfaffenbach

BERLIN (Reuters) - Combined support for German Chancellor Angela Merkel’s conservative alliance and their partners, the left-leaning Social Democrats (SPD), has hit a record low for any such ‘grand coalition’ government, according to a survey published on Sunday.

Germany’s two biggest and most established parties have had a torrid summer, blighted by infighting over immigration that is flaring up again after violent right-wing protests in the eastern city of Chemnitz followed the fatal stabbing of a German man, for which two migrants were arrested.

The survey by pollster Emnid for the weekly newspaper Bild am Sonntag had support for Merkel’s Christian Democratic Union (CDU) and their Bavarian allies, the Christian Social Union (CSU), down by one percentage point on the week to 29 percent.

In last September’s federal election, the CDU/CSU bloc won 32.9 percent of the vote.

The poll put support for the SPD down two points to 17 percent. In the last election, the SPD won 20.5 percent of the vote.

Their combined score of 46 percent was the lowest for any CDU/CSU/SPD coalition - a combination that also held power in 2005-09 and 2013-17 - in Emnid’s poll for the Bild am Sonntag. The pollster surveyed 2,472 voters between Aug. 30 and Sept. 5.

Support for the anti-immigration Alternative for Germany (AfD) was unchanged from the previous week at 15 percent, the poll showed. The far-left Linke gained one point to 10 percent. The ecologist Greens were unchanged at 14 percent and the business-friendly Free Democrats (FDP) remained at 9 percent.

Support for other parties rose two points to 6 percent.