The United Nations high commissioner for refugees said on Saturday the world waited far too long to respond to the refugee crisis sparked by the wars in Syria and elsewhere, though rich countries now appear to understand the scale of the problem.

"Unfortunately only when the poor enter the halls of the rich, do the rich notice that the poor exist," U.N. refugee chief Antonio Guterres told Reuters in an interview on the sidelines of the annual gathering of world leaders at the U.N. General Assembly.

"Until we had this massive movement into Europe, there was no recognition in the developed world of how serious this crisis was," he said. "If, in the past, we had more massive support to those countries in the developing world that have been receiving them and protecting them, this would not have happened."

The sudden arrival in Europe of tens of thousands refugees from Syria, Iraq, Afghanistan and elsewhere, many abandoning refugee camps in Turkey, Jordan or Lebanon, has stirred sharp disagreement between European Union countries on how to "process" and accommodate them.

While governments such as Germany have proven more welcoming, Eastern European countries have resisted plans for quotas to disperse arefugees.

For years, Lebanon, Turkey and Jordan have struggled to cope with millions of refugees from Syria's 4-1/2-year civil war.

"The refugees are living worse and worse," he said. "They're not allowed to work, the overwhelming majority of them live below the poverty line. It's more and more difficult for them to have any hope in the future.

"Without peace in Syria, and without massive support to the neighbouring countries ... we risk a massive exodus" of refugees from Turkey, Jordan and Lebanon.

He also disputed some assessments, including Hungary's, that most of the people reaching the EU's doorsteps from the Balkans were economic migrants, not refugees who deserve protection. Most of them are genuine refugees, he said.

U.N. Secretary-General Ban Ki-moon is convening a high-level meeting on Wednesday on the refugee and migration crisis.

Guterres said rich countries appeared to be finally waking up.

"I think political leaders are starting to understand ... the scale of the problem and the need to have a much stronger response, response in humanitarian aid.

"One of the reasons that refugees started to move in such big numbers was because international assistance declined," he said, adding that Turkey, Jordan and Lebanon would need billions of dollars in assistance to cope with the refugees.