More than 131,000 migrants and refugees have reached Europe via the Mediterranean this year, more than the total number in the first half of 2015, the United Nations said today.

Out of a total of 131,724 people who have arrived on Europe's shores this year, 122,637 landed in Greece and most were fleeing the conflict in Syria, the UN's refugee agency (UNHCR) said.

The agency said an estimated 24,000 migrants in Greece were in need of accommodation as of Monday night.

Huge blockages of people have built up in the country after European nations including neighbouring Macedonia set tight limits on migrants entries.

"Europe is on the cusp of a largely self-induced humanitarian crisis," the agency warned, accusing EU governments of fuelling the chaos and suffering by resorting to "inconsistent practices" in response to the migrant crisis.