Berlin: Voters flocked to the polling booths on Sunday in a Berlin city election, in which Chancellor Angela Merkel’s conservatives look set to suffer their second electoral blow in two weeks as voters express unease with her refugee-friendly policy.

The anti-immigrant Alternative for Germany (AfD) is expected to profit from a popular backlash over Merkel’s decision a year ago to keep borders open for refugees and the party is poised to enter its tenth regional assembly out of Germany’s 16 states.

Voting in the German capital started at 8am (0600 GMT) and some 2.5 million people are eligible to decide who should represent them in the Berlin city assembly.

Queues formed in front of many polling stations, with the sunny weather helping to boost the turnout. At noon, some 25 per cent had cast their vote, 6 points more than the midday turnout during the last election in 2011, authorities said.

Polls point to heavy losses for Merkel’s Christian Democrats (CDU) in the vote that means the centre-left Social Democrats (SPD) may be able to ditch them from their current coalition.

That would likely raise the pressure further on Merkel one year before a federal election and could deepen divisions within her conservative camp.

Polling stations will close at 6pm (1600 GMT) and public broadcasters will publish exit polls shortly afterwards. First projections are expected roughly half an hour later.

A drubbing in the eastern state of Mecklenburg-Vorpommern two weeks ago triggered calls from Merkel’s conservative allies in Bavaria to toughen up her refugee policy with measures such as introducing a cap of 200,000 asylum seekers per year.

Merkel rejects such a limit and defends her approach to find a European solution to the migration issue by securing the continent’s external borders, agreeing on migration deals with countries like Turkey and distributing refugees across Europe.

The recent election losses have even raised questions about whether Merkel, Europe’s most powerful leader, will stand for a fourth term next year but her party has few good alternatives so she still looks like the most likely candidate.

The latest Berlin poll by Forschungsgruppe Wahlen for ZDF public broadcaster put the CDU on 18 per cent, down 5 points and far behind the SPD’s projected 23 per cent. It put the AfD on 14 per cent, the leftist Die Linke at 14.5 per cent and the ecologist Greens on 15 per cent.

The AfD has campaigned heavily on the refugee issue, playing to voters’ fears about the cost of the roughly 1 million asylum seekers who entered Germany last year and about their integration.

Security, especially after 20 people were injured in two attacks claimed by Daesh in Bavaria in July and deadly Islamist militant attacks in neighbouring France and Belgium earlier in the year, are also a concern to voters.

The SPD, Merkel’s junior coalition partner at the federal level, wants to form a coalition with the Greens and, if needed, the leftist Die Linke.

Berlin’s SPD Mayor Michael Mueller has sharply criticised the AfD’s migration policy during the campaign, saying a double-digit score for the right-wing party would be seen around the world as the rebirth of the Nazis.