Chancellor Angela Merkel stood firm on her decision to open Germany to refugees despite mounting criticism, telling citizens in her New Year’s address on Thursday that the record influx is “an opportunity for tomorrow”.

Ms Merkel has earned praise at home and abroad for her decision to allow in a record wave of refugees, about half from war-torn Syria. But with one million asylum seekers arriving in 2015 alone, opposition and doubts are growing, including within her own conservative camp and among the population.

Acknowledging the immense task of dealing with the massive influx, Mr Merkel braced Germans for more challenges ahead and made a strong call for unity. “Next year is about one thing in particular: Our cohesion,” she said. “It is important we don’t allow ourselves to be divided.

“It is crucial not to follow those who, with coldness or even hatred in their hearts, lay a sole claim to what it means to be German and seek to exclude others,” she urged, in a reference to ring-wing populists and xenophobic street rallies.

The efforts put in to cope with the challenges would be worth it in the end because “countries have always benefitted from successful immigration, both economically and socially”, she said, adding, “I am convinced that, handled properly, today’s great task presented by the influx and the integration of so many people is an opportunity for tomorrow.”

Germany took in almost 1.1 million refugees this year, four times more than last year, the Saechsische Zeitung daily reported.