Immigration can enrich Germany and even jog Germans to learn more about Christianity, Chancellor Angela Merkel said on Monday, shrugging aside the growing unease in her coalition over the influx of nearly a million migrants this year.

Speaking a day after the far-right National Front pulled off a historic win in neighbouring France,Merkel lauded the contribution to Germany's economy and society of the "Gastarbeiter" (guest workers) who came in the postwar decades.

"Many of you have experiences that we can't offer," she told the Gastarbeiter and their descendants, many of whom came from Muslim Turkey and the Balkans, at an event marking the 60th anniversary of a program that boosted then-West Germany's economy while turning it into a more multi-ethnic society.

Their familiarity with more than one culture has been an "incredible plus" in an increasingly globalized and shrinking world, Merkel said, adding: "Nobody must forget their roots."

Shortly after Merkel spoke, Interior Minister Thomas de Maiziere told a news conference that some 965,000 asylum seekers had arrived in Germany this year as of the end of November.

Germany is taking the majority of the migrants fleeing to Europe from war and deprivation in the Middle East, Africa and Asia, and expects around a million to arrive this year.

Many local authorities are struggling to cope with the influx and some Germans, not least among Merkel's conservatives, fret about the long-term social and cultural implications of such large-scale immigration.

Merkel, a Protestant pastor's daughter who grew up in communist East Germany, has held onto her accommodating message toward the refugees despite strong pressure within her coalition government to stem the flow.

She described integration as a two-way process and a "coming together" of migrants and those already in Germany.

"If one has to look again at the Bible because one talks to someone about the Koran, that is not a bad thing either, as the Germans aren't as well versed in the Bible as they sometimes make out," she added.

"Curiosity enriches us"

The refugee crisis has revived support for Germany's AfD anti-immigrant party, which placed third nationally for the first time last month, at 10.5 per cent, in a survey for pollsters INSA.

Despite the concerns about the refugee influx, Merkel shows no sign of losing her grip on power as she faces no legitimate challengers on the right or left.

In championing the benefits of immigration, Merkel has shown a marked turnaround from her position just five years ago. In 2010, she declared that multi-culturalism in Germany had been an abject failure.

Her message was quite different on Monday.

"We must learn, also like those who have lived in Germany for hundreds of years, that openness, that curiosity for other cultures doesn't take anything away from us, but rather enriches us," the chancellor said.