Fear for unforeseen circumstances, German business leaders fear nationalism.

German business leaders fear that deep divisions over how to handle the refugee crisis and growing nationalism among member states could break up the European Union, according to five of the country's biggest industry bodies.

The arrival of hundreds of thousands of people fleeing war and poverty in countries such as Syria and Iraq in Europe this year has frayed ties between European nations that were already strained by the euro zone financial crisis.

Added to that, rising nationalism could endanger Europe's wealth, economic success and security, the presidents of Germany's most prominent business groups told Reuters.

"Next year will be a crucial year for Europe," BDI industry association leader, Ulrich Grillo, said. "I'm very worried about the future of the European Union."

Lack of solidarity within the bloc meant Europe was risking all the achievements of the previous decades, Association of Skilled Trades president, Hans Peter Wollseifer, said.

"I would like to see a strong symbol for the unity of Europe," he said.

Germany's BGA wholesalers and exporters body leader, Anton Boerner, said Europe pulling further apart was one of the biggest risks for next year.

Germany is looking to EU partners to help manage the refugee crisis but is running up against resistance from some countries, particularly in eastern Europe.

The influx has raised security concerns and boosted support for euroskeptic parties across Europe, from Germany's AfD party to France's National Front, the Law and Justice government in Poland and Britain's anti-EU UK Independence Party.

"Europe has been in difficult water for a long time," Association of German Chambers of Commerce and Industry (DIHK) head, Eric Schweitzer, said.

National answers for international problems were no longer enough, he said, and Europe only had weight in the world when its member states acted together.

In addition to the refugee crisis, European officials are grappling with Britain's demands for EU reform ahead of a referendum on its membership of the bloc.

The head of Germany's BDA employers association, Ingo Kramer, called on the EU to take Britain's demand for change seriously in order to keep the country in the union.