BERLIN -- German Chancellor Angela Merkel on Sunday slammed those countries in Europe who say they won't take in Muslim refugees, a position that several eastern European governments have taken in response to the influx of migrants from the Islamic world.

Merkel said she was hopeful that European Union members would reach an agreement on outstanding questions arising from the migrant crisis, one of which is how to fairly distribute asylum-seekers among all the bloc's 28 member states.

She told German public broadcaster ARD that "everybody has to do their bit" and didn't rule out the possibility of letting some countries take in fewer migrants if they contribute more financially instead.

"How the individual components are weighted will have to be seen," said Merkel.

But she reiterated her stance that blocking refugees based on their religion was misguided.

"What I continue to think is wrong is that some say 'we generally don't want Muslims in our country, regardless of whether there's a humanitarian need or not,"' she said. "We're going to have to keep discussing that."

Her comments come almost a year after Merkel's decision to allow hundreds of thousands of migrants stuck in other European countries to come to Germany.

That move prompted a further wave of migration through the Balkans that culminated in the daily arrival of more than 10,000 asylum-seekers at German borders at one point.

Officials have spoken of more than a million arrivals in 2015, but Germany's top migration official said the actual figure was likely lower once duplicate registrations and people who travelled on to other countries are excluded.

Frank-Juergen Weise, the head of the Federal Office for Migration and Refugees, said in an interview in the German weekly Bild am Sonntag that he expects a sharp drop in numbers in 2016 compared with last year.

Weise told German weekly Bild am Sonntag that his agency is planning for between 250,000 and 300,000 new arrivals this year.

The influx prompted countries such as Hungary to sharply criticize Merkel, and even accuse her of threatening Europe's stability.

In Germany, anti-migrant feeling has increased too. A nationalist party to the right of Merkel's Christian Democrats has received a surge in support and chancellor, who has stuck by her motto "we will manage," has seen her popularity ratings fall.

A poll published Sunday by Bild am Sonntag found that 50 per cent of respondents opposed a fourth term for Merkel, should she decide to run again in 2017. The survey of 501 voters, conducted Aug. 25 by the research firm TNS Emnid, had a margin of error of 4.4 percentage points.

In her interview Sunday, Merkel declined to be drawn on whether she would run again, or even when she might announce her intention to stand again.