Irish aid agency Goal has warned the migrant crisis could be Europe's biggest political issue since the Second World War.
The UK, France and Germany are calling for refugees arriving in southern Europe to be fingerprinted to identify those most in need of protection.
They also want a special meeting of EU officials to discuss the crisis within the next two weeks.
Goal's COO Jonathan Edgar, who has just returned from a fact-finding mission on the Greek islands, said: "I turned up in (the island of) Kos with 600 refugees from Syria that day - these are the numbers that are coming through.
"Every European nation needs to take its fair share of the responsibility in dealing with this crisis.
"If this is not dealt with at source inside Syria and on the borders with Syria, it will become one of the biggest political issues that we have faced in Europe for many years…I think since the Second World War."
He said there needed to be investment and support for the livelihoods of people inside Syria, as well as funding for measures to deal with the pressure points in Turkey, that would stop migrants travelling further south and west.
"They don't want necessarily to end up in Dublin, London or Berlin. They want to stay in Syria, but they feel they have no other option," he said.
Meanwhile, three children remain seriously ill in hospital with suspected dehydration, after they were found in Austria in a lorry carrying 26 migrants.
A fifth man suspected of being involved in the deaths of 71 migrants found in a truck in Austria has been detained in Hungary, Hungarian police said.
A national police statement said the Bulgarian national was arrested on Saturday evening. Police said they will seek to have him held in custody on suspicion of human trafficking.
On Saturday, a court in the central city of Kecskemet – from where prosecutors say the truck departed – placed four other suspects under preliminary arrest pending possible indictment.
Those men, three Bulgarians and an Afghan, were arrested on Thursday in southern Hungary.
The truck with the dead migrants was found earlier that day parked along the Budapest-to-Vienna highway.
Austrian experts are performing autopsies on the victims: 59 men, eight women and four children.
In another case, 26 people from Syria, Afghanistan and Bangladesh were discovered crammed inside the truck on the German border.