Almost 500,000 refugees crossed to Greece in the last quarter of 2015, EU agency Frontex reported on Thursday.
Most of the refugees have moved to the Balkans, the agency said.
Collecting data on border crossings working along with the EU, Frontex recorded 484,000 cases of irregular refugee crossings on the Eastern Mediterranean route from Turkey to Greece between the months of October and December and 466,000 on the Western Balkan route.
Forty six percent of those arriving in Greece, mostly to islands in the Aegean, said they are Syrian and 28 percent Afghan.
Arrivals in Italy from Libya have decreased while arrivals in Spain from Morocco have increased.
Nearly 3,000 illegal crossings were recorded in the fourth quarter of 2015 on the Western Mediterranean route, Frontex added.
In the meantime, Greece is facing even more economic risks deriving from Europe’s refugee crisis while the country is struggling to manage the refugee flow and needs assistance, the Organisation for Economic Cooperation and Development (OECD) said on Thursday.
"The refugee crisis creates significant problems for the Greek economy and growth," OECD Secretary-General Angel Gurria told reporters after meeting Greek Prime Minister Alexis Tsipras in Athens.
"Greece needs to receive substantial support to deal with this new challenge. No single country can address this challenge on its own," he said.
Tsipras said that Greece will meet economic growth targets in the third quarter of 2016, while noting that the refugee crisis could have a significant economic impact on the country, which is already in a financial crisis.
However, Gurria said there will be no economic growth for the country this year.