At least 850,000 people are expected to cross the Mediterranean seeking refuge in Europe this year and next, the United Nations said on Tuesday, giving estimates that already look conservative.
The U.N. refugee agency UNHCR called for more cohesive asylum policies to deal with the growing numbers.
Many are refugees from Syria, driven to make the voyage by intensified fighting there and worsening conditions for refugees in surrounding countries due to funding shortfalls in aid programs, UNHCR said.
"In 2015, UNHCR anticipates that approximately 400,000 new arrivals will seek international protection in Europe via the Mediterranean. In 2016 this number could reach 450,000 or more," it said in an appeal document.
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UN says 850,000 to cross sea to Europe in 2015 and 2016
FILE - In this Sept. 3, 2015 file photo, a woman rescued with other migrants off the Libyan coast peers through a gate on the Norwegian ship Siem Pilot to get her first sight of the island of Sardinia as they sail in the Mediterranean sea towards the Italian port of Cagliari. (AP Photo/Gregorio Borgia, File)
Migrants sit on the deck of the Belgian Navy vessel Godetia after they were saved at sea during a search and rescue mission in the Mediterranean Sea off the Libyan coasts, Wednesday, June 24, 2015. Hundreds of migrants were rescued on Tuesday by the Godetia, which is part of a EU Navy vessels fleet taking part in the Triton migrants rescue operation. (AP Photo/Gregorio Borgia)
FILE - In this Sept. 1, 2015 file photo, migrants disembark from the catamaran Terra Jet at the Athens' port of Piraeus. About 1,800 refugees arrived from the northeastern Aegean island of Lesbos as the country has been overwhelmed by record numbers of migrants this year. (AP Photo/Thanassis Stavrakis, File)
Syrian refugees walk among fields at the border town of Idomeni, northern Greece to cross the border and enter Macedonia, on Wednesday Aug. 26, 2015. The U.N.âs refugee agency said it expects 3,000 people to cross Macedonia daily in the coming days as Greece has borne the brunt of a record number of refugees and migrants heading to Europe. (AP Photo/Santi Palacios)
A migrant jumps a fence as he attempts to access the Channel Tunnel in Calais, northern France, Wednesday, Aug. 5, 2015. Thousands of migrants have been scaling fences near the Channel Tunnel linking the two countries and boarding freight trains or trucks destined for Britain. (AP Photo/Emilio Morenatti)
A migrant, hiding under a train, tries to sneak on a train towards Serbia, at the railway station in the southern Macedonian town of Gevgelija, on Monday, Aug. 17, 2015. Over 1,000 migrants from Middle East, Asia and Africa, enter Macedonia daily from Greece, heading north through the Balkans on their way to the more prosperous European Union countries. The migrants' urgency to reach Europe has become more pronounced as they race to reach Hungary before the Hungarian government finishes building a razor-wire fence. (AP Photo/Boris Grdanoski)
FILE - In this Aug. 12, 2015 file photo, migrants try to board a train that would take them toward Serbia at the railway station in the southern Macedonian town of Gevgelija. Macedonia is facing an increasing pressure of migrants flow on its southern and northern borders with Greece and Serbia as thousands of migrants from Middle East, Asia and Africa are heading north through the Balkans on their way to the more prosperous European Union countries. (AP Photo/Boris Grdanoski, File)
A woman looks out of a train that was stopped in Bicske, Hungary, Friday, Sept. 4, 2015. Over 150,000 peoplel have reached Hungary this year, most coming through the southern border with Serbia. Many apply for asylum but quickly try to leave for richer EU countries. (AP Photo/Petr David Josek)
A migrant lies on the track with a baby as she is detained in Bicske, Hungary, Thursday, Sept. 3, 2015. Over 150,000 migrants have reached Hungary this year, most coming through the southern border with Serbia. Many apply for asylum but quickly try to leave for richer EU countries. (AP Photo/Petr David Josek)
FILE - In this Sept 2, 2015 file photo, migrants crowd the bridge of the Norwegian ship Siem Pilot sailing along the Mediterranean sea. The Siem Pilot is carrying to the Italian Port of Cagliari hundreds of migrants rescued in several operations in the Mediterranean sea. (AP Photo/Gregorio Borgia, File)
A paramilitary police officer carries the lifeless body of an unidentified migrant child, lifting it from the sea shore, near the Turkish resort of Bodrum, Turkey, early Wednesday, Sept. 2, 2015. A number of migrants are known to have died and some are still reported missing, after boats carrying them to the Greek island of Kos capsized. (AP Photo/DHA) TURKEY OUT
FILE - In this Aug. 31, 2015 file photo, Macedonian police officers help a dehydrated migrant, who is accompanied by a fellow migrant trying to get to a transit center after crossing the border from Greece to Macedonia, near southern Macedonian town of Gevgelija. Thousands of migrants have poured into Macedonia and boarded trains and buses that are taking them a step closer to the European Union. (AP Photo/Boris Grdanoski, File)
A migrant man holding a boy react as they are stuck between Macedonian riot police officers and migrants during a clash near the border train station of Idomeni, northern Greece, as they wait to be allowed by the Macedonian police to cross the border from Greece to Macedonia, Friday, Aug. 21, 2015. Macedonian special police forces have fired stun grenades to disperse thousands of migrants stuck on a no-man's land with Greece, a day after Macedonia declared a state of emergency on its borders to deal with a massive influx of migrants heading north to Europe. (AP Photo/Darko Vojinovic)
FILE - In this Aug. 13, 2015 file photo, a man carries a girl in his arm as they arrive with other migrants just after dawn on a dinghy after crossing from Turkey to the island of Kos in southeastern Greece. Greece has become the main gateway to Europe for tens of thousands of refugees and economic migrants, mainly Syrians fleeing war, as fighting in Libya has made the alternative route from north Africa to Italy increasingly dangerous. (AP Photo/Alexander Zemlianichenko, File)
FILE - In this Aug. 13, 2015 file photo, a family of refugees hug each other after successfully arriving on a dinghy on the Greek island of Kos after crossing overnight from Turkey to Greece. Greece has become the main gateway to Europe for tens of thousands of refugees and economic migrants, mainly Syrians fleeing war, as fighting in Libya has made the alternative route from north Africa to Italy increasingly dangerous. (AP Photo/Alexander Zemlianichenko, File)
FILE - In this Aug. 12, 2015 file photo, children play on a train track as migrants wait for a train heading toward Serbia, at the railway station in the southern Macedonian town of Gevgelija. Macedonia is facing an increasing pressure of migrants from the Middle East, Asia and Africa flowing into its southern and northern borders with Greece and Serbia and heading toward more prosperous European Union countries. (AP Photo/Boris Grdanoski, File)
A dinghy with migrants sails under a rising sun a few miles off a coast of the southeastern island of Kos, Tuesday, Aug. 11, 2015. Fights broke out among migrants on the Greek island of Kos Tuesday, where overwhelmed authorities are struggling to contain increasing numbers of people arriving clandestinely on rubber dinghies from the nearby Turkish shore. (AP Photo/Yorgos Karahalis)
FILE - In this Aug. 5, 2015 file photo, a migrant sits at a camp set near Calais, northern France. Thousands of migrants have been scaling fences near the Channel Tunnel linking the two countries and boarding freight trains or trucks destined for Britain. (AP Photo/Emilio Morenatti, File)
FILE - In this Aug. 5, 2015 file photo, a migrant sleeps inside a tent at a camp set near Calais, northern France. Thousands of migrants have been scaling fences near the Channel Tunnel linking the two countries and boarding freight trains or trucks destined for Britain. (AP Photo/Emilio Morenatti, File)
FILE - Aug. 4, 2015 file photo, migrants walk along the train tracks after crossing a fence as they attempt to access the Channel Tunnel in Calais, northern France. Thousands of migrants have been scaling fences near the Channel Tunnel linking the two countries and boarding freight trains or trucks destined for Britain. (AP Photo/Emilio Morenatti, File)
In this Monday, April 20, 2015, file photo, the Tunisian navigator Mohammed Ali Malek, and one of the survivors of the boat that overturned off the coast of Libya, waits to disembark from Italian Coast Guard ship Bruno Gregoretti, at Catania Harbor, Italy. The United Nations refugee agency said Tuesday that more than 800 people were believed to have drowned in the weekend sinking of a boat packed with migrants trying to reach Europe, making it the deadliest such disaster in the Mediterranean. Prosecutors said that after ship captain Mohammed Ali Malek rammed a vessel, terrified migrants rushed around the overcrowded boat, which was already unbalanced from the collision. (AP Photo/Alessandra Tarantino, File)
Migrants wait to disembark from the Irish naval ship Le Eithne, at the Palermo harbor, Italy, Saturday, May 30, 2015. The Italian coast guard says it has coordinated the rescue of more than 4,000 migrants off Libya's coast in 22 separate operations. The rescues, from 13 boats and nine motorized rubber dinghies, took place Friday. Cargo ships and Irish and German navy vessels helped Italian military craft in Friday's rescues. (AP Photo/Alessandro Fucarini)
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Spokesman William Spindler said the prediction for this year was close to being fulfilled, with 366,000 having already made the voyage. The total will depend on whether migrants stop attempting the journey as the weather gets colder and the seas more perilous.
So far, the numbers do not appear to have slowed down as the colder months approach, with many appearing spurred on by Germany's announcement that it will ease the rules for Syrians seeking refuge who first reach the European Union through other countries.
A single-day record 7,000 Syrian refugees arrived in the former Yugoslav republic of Macedonia on Monday, while 30,000 are on Greek islands, most of them on Lesbos, it said.
Many arrive first in Greece, then leave the EU to travel up through the Balkans to Hungary and onward to Germany.
"So obviously the discussions this week in Europe are taking even on greater urgency because it obviously cannot be a German solution to a European problem," UNHCR spokeswoman Melissa Fleming told a news briefing.
UNHCR chief Antonio Guterres called for an increase in the number of legal ways for refugees to come to Europe, such as an increase in number of visas and ways to reunite people with their families.
"I am convinced that with the proper instruments in place, this will be much easier to manage," he told a news conference in Paris.
Germany told its European partners on Monday they must take in more refugees as it handles record numbers of asylum seekers.
The European Union's executive Commission is expected to unveil a program this week that would redistribute 160,000 asylum seekers who arrive in Italy, Hungary and Greece.
Peter Sutherland, Special Representative of the U.N. Secretary-General for Migration and Development, called for a "harmonized system" and "fair allocation" in the European Union.
He said Europe's "Dublin rules" requiring asylum seekers to apply in the first EU country they reach would have to be amended, or they could jeopardize the principles of border control-free travel in the bloc's Schengen zone.
"Coherence is going to require leadership and leadership before we see the destruction of great achievements like the Schengen agreement," he warned. "I think Dublin doesn't work."
Other countries - including the United States, wealthy Gulf states and Japan - must face their responsibilities, he said.
Germany's decision last month to open its doors to Syrians who arrived elsewhere in the EU has brought the issue sharply into focus, as did images last week of a drowned Syrian toddler washed up on a Turkish beach, which appeared on newspaper front pages across the continent.