Migrants protest being stuck in Bicske, Hungary. (Balazs Mohai/EPA)

LONDON — Arguing in favor of more refugees has become difficult for Europe's mainstream politicians in recent weeks. Sexual assault allegations against asylum seekers in Cologne and other cities have had an immense impact on the public debate in Germany -- arguably Europe's most welcoming nation toward refugees at the moment.

Amid the growing discontent, the International Monetary Fund (IMF) urged governments to consider potential economic benefits of new arrivals in a study published Wednesday. Based in Washington D.C., the international organization's voice is among the most influential in world economics.

Many of the researchers' observations are based on economic migration rather than influxes caused by war. Drawing on previous experiences, the economists expected short- as well as long-term benefits, particularly in the countries that have become the most common destinations for migrants, including Germany, Sweden and Austria. Public spending on refugees -- on housing, for instance -- could temporarily decrease unemployment by providing jobs to residents living nearby and keeping local food distribution companies and contractors busy with work.

In the long-term, Europe's governments will face challenges in integrating the hundreds of thousands of refugees who arrived last year alone, the economists acknowledged. But "good policies will make an important difference," they said.

"While native workers often have legitimate concerns about the impact of immigrants on wages and employment, past experience indicates that any adverse effects are limited and temporary," they wrote. For instance, subsidizing refugee wages through public funds, geographical mobility, as well as making it easier for earlier asylum seekers to get jobs could prevent negative economic repercussions.

The study comes at a sensitive time: On Wednesday, Austria announced an upper refugee limit. German Chancellor Angela Merkel continues to face criticism -- even from members of her own party. And in Britain, Europe's crisis is increasingly used as an argument by those favoring an exit from the European Union.

The IMF study will play into the hands of those who are still seeking a common E.U. response to the refugee crisis, despite recent setbacks. National governments have recently taken the lead and implemented more restrictive policies. Denmark, for instance, secured a parliamentary majority for a controversial bill last week that would make it harder for refugees to enter the country and stay.

Although many nations are concerned about immigrants' impact on their cultures and national identities, economic considerations have always played a role, as well. When a majority of Germans still supported Merkel's decision to allow an unlimited number of refugees into the country last summer, one key argument was that German companies desperately needed younger workers. Many people, including company executives, embraced her policies.

Hundreds of thousands of jobs remained unfilled last year because of a lack of qualified applicants. Hence, CEOs urged Merkel to turn the refugee challenge into an opportunity. "Most refugees are young, well educated and highly motivated. Those are exactly the people we're searching for," Dieter Zetsche, the head of car manufacturer Daimler, was quoted as saying.

"What we're experiencing right now is something that will occupy and change our country in the coming years. We want this change to be positive," Merkel was quoted as saying back then. With a quickly shrinking working-age population and low birth rates, it seemed like only a matter of time until the country's welfare system would collapse. In order to finance health care and other programs for an aging population, Germany needed an influx of younger men and women.

Based on the performance of other foreign-born workers in Germany, the IMF economists conclude that "the analysis of the German experience shows that immigrants make substantial contributions to the economy but face considerable obstacles in the labor market that are overcome only gradually."

Germany was already Europe's biggest and most prosperous economy before the refugee surge started. According to the IMF, the flow of new people is unlikely to threaten that position and could even strengthen it. But other E.U. countries, whose populations are also rapidly aging, may be missing out on an opportunity.