GENEVA : Some 168,000 migrants and refugees made the perilous journey across the Mediterranean to Europe in September, marking the highest monthly figure on record, the United Nations said Friday.

"In September, 168,000 crossed the Mediterranean. That's the highest monthly figure ever, and almost five times the number seen in September 2014," UN refugee agency spokesman Adrian Edwards told reporters.

He said the September figure was more than two thirds of the total number of arrivals in 2014, when 219,000 migrants and refugees crossed the Mediterranean to Europe.

So far this year, almost 530,000 people have made the voyage, with nearly 400,000 of them arriving in Greece and 131,000 arriving in Italy. Around 3,000 people have died attempting the journey since January.

Edwards said Greece, which recorded 43,500 arrivals throughout 2014, had seen 153,000 migrants and refugees land on its shores last month alone.

A full 97 percent of those arriving in Greece are fleeing from the world's 10 top refugee-producing countries, including Syria, Afghanistan and Iraq, he stressed.

This week, however, there had been a "noticeable drop" in arrivals to Greece due to poorer weather, Edwards said.

While some 6,600 people had landed on Greek shores on September 25, the number plunged to 2,200 the next day and as low as 1,500 on Thursday.

But any improvement in the weather was "likely to bring another surge in sea arrivals," he said.

Edwards reiterated UNHCR's call for Europe to urgently implement a plan for relocating 120,000 refugees across the continent, despite fierce opposition from central and eastern states.

The UN agency also wants Europe to establish "robust facilities to receive, assist, register and screen all people arriving by sea," he said. "These are steps needed for stabilising the crisis."

UNHCR on Thursday said it now expects 700,000 people to reach Europe by sea this year, and at least the same number again in 2016.