Three German states hold elections for regional parliaments on Sunday which are expected to show strong performance of The Alternative for Germany (AFD), a right-wing group opposed to Chancellor Angela Merkel’s open-door policy on refugees.

The elections - the first since the refugee crisis began – are seen as a direct challenge to Merkel as voters' concerns about the record migrant influx in Germany may boost support for AfD.

The three states are Baden Wurttemberg and Rhineland-Palatinate in the west and Saxony-Anhalt in the east. Their combined population is about 17 million, around a fifth of Germany’s population.  

Polls suggest the results will be uncomfortable for both Merkel's centre-right conservative Christian Democratic Union (CDU) and her partners in the national government, the centre-left Social Democrats.

AfD, which has campaigned against Merkel's open-door policy on migrants, is expected to enter all three state parliaments, according to polls conducted earlier this week.

A survey for German broadcaster ZDF has puts the AfD on 18% of the vote in Saxony-Anhalt, 11% in Baden-W?rttemberg, 9% in Rhineland-Palatinate.

More than a million people - mostly Syrians - arrived in Germany last year. Merkel’s open-door policy toward refugees has stirred deep divisions both in German society and the CDU as the Chancellor has rejected imposing a cap on new arrivals, favoring instead a plan to distribute refugees across the 28 EU member states.

A failure to win at least two of the three states would be a major setback for Merkel, who is trying to rally support among European leaders to strike a deal with Turkey to curb the migrant influx, Deutsche Welle has commented.

The AfD has said ahead of the vote that it will seek a ban on minarets and the Muslim call to prayer which is often played through loudspeakers throughout the day, according to Bild newspaper. They also plan to seek a ban on halal slaughter saying that they believe the special religious rules are contrary to the German Animal Protection Act.