The sheer number of migrants coming to Europe make this year's crisis unparallelled in recent times - but Europe has the capacity and an "obligation" to absorb them, the OECD says.
"The current humanitarian crisis is unprecedented with an appalling and unacceptable human cost," the Paris-based body said in its annual report on migration.
The OECD said up to one million asylum applications could be made in Europe this year and between 350,000 and 450,000 people could be granted the status of refugee or similar - and it warned that the flow of migrants was unlikely to end any time soon.
"Given the complexity of its main driving forces, there is unfortunately little hope that the situation will improve significantly in the near future," the report said.
Compared with previous years, migrants are flowing in from more countries and along a wider range of routes, the report said.
Last year, Syrians fleeing the war in their homeland accounted for 21 per cent of asylum seekers, while people from Kosovo represented nearly 10 percent of the applications and Eritreans 6.4 percent.
"More than in previous crises, asylum seekers are very diverse in terms of country of origin, profile and motivation," the OECD said, adding this "increases the pressure on asylum systems in different countries".
It also noted advances in communication technology that allowed migrants to find out about new routes faster, coupled with the emergence of new smuggling routes, "lead to rapidly changing situations".
The influx of asylum seekers is "a new experience" for several European countries such as Hungary, which has taken the hardest line to prevent migrants entering the country.
It is essential for European Union leaders to reach agreement soon on how the refugees will be distributed among member states, the OECD said, because the systems now in place "have not ensured a fair burden-sharing between countries".
Overall, however, Europe has the economic resources and the ability to absorb hundreds of thousands of migrants, it said.
"The key message is that Europe has the means and the experience to respond to this crisis," said Jean-Christophe Dumont, head of the OECD's International Migration Division.
Given time, migrants can become valuable contributors to the economic and social health of the countries where they make their homes, the report said.
"The facts are there - migration does not have a negative impact on the labour market, it does not deepen budget deficits. Immigrants contribute more than they receive in individual benefits," Dumont said.
However, European leaders have a serious challenge in convincing voters migrants could be a good thing, he warned.
"(Migration) does not threaten our identity. But of course it's a message that you can't get across quickly. You have to explain it and repeat it."