Ten times as many migrants and refugees arrived in Europe by sea in the first six weeks of the year as in the same period of 2015, and the number of deaths also soared, according to the International Organisation for Migration (IOM).
The organisation said the number of arrivals topped 76,000, and the number of deaths shot up to 409 on Mediterranean routes from 69 in the first six weeks of 2015.
The IOM also predicted no fall in the number of arrivals in Europe and said next month Greece would receive its one millionth arrival since the migrant crisis began.
More than 1.1 million people fleeing poverty, war and repression in the Middle East, Asia and Africa reached Europe's shores last year, most of them heading for Germany.
Around half the arrivals are refugees from the Syrian war, the UN Refugee Agency (UNHCR) says.
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The IOM reported 70,365 migrants and refugees had arrived by sea in Greece so far this year, and 5,898 in Italy.
Some 319 have died while crossing the eastern Mediterranean from Turkey to Greece and 90 on the central route between North Africa and Italy.
IOM spokesman Joel Millman said the organisation did not expect the number of migrant and refugee arrivals in Europe to fall in the foreseeable future.
"There are more concurrent crises around than we've ever seen at one time," he said.
"Conditions on the ground in the countries that are feeding the migrant crisis are largely unchanged, so we think the numbers will probably stay the same."
The short eastern Mediterranean crossing is safer than the central Mediterranean route, where there were a number of major sinkings in 2015.
But Millman said the number of Aegean deaths had suddenly shot up at the end of last year, when small boats sank almost daily - possibly showing that migrants were using less seaworthy boats.
