All EU countries need to help southern neighbours, where most migrants are arriving, European Commissioner Guenther Oettinger has said.
Mr Oettinger was speaking ahead of a mini-summit on migration in Brussels on Sunday.
He told reporters in Luxembourg that the meeting should serve as "a reminder of the way towards European unity".
"I think that the whole of Europe must show solidarity towards those who are most affected, the Greeks, Malta, Cyprus, Bulgaria, Italy and Spain, to ease their burden and to reimburse and honour a part of their costs and efforts," he said.
A number of former Communist countries in the European Union will not be represented at the summit, following a meeting of the 'Visegrad 4'.
Hungarian leader Viktor Orban hosted a meeting of the leaders of Poland, Czech Republic and Slovakia yesterday.
The four confirmed they would not attend Sunday’s talks, taking a veiled swipe at German Chancellor Angela Merkel by accusing countries of pushing the issue for domestic political reasons.
"We understand there are domestic political difficulties in some countries but that cannot lead to pan-European haste," Mr Orban said.
"We understand that there will ... be a mini-summit on Sunday but we would like to state clearly that the prime ministers of V4 agreed that they will not go to that."
Italian Prime Minister Giuseppe Conte has also said a draft EU accord on migration had been withdrawn after he clashed with Ms Merkel.
The withdrawn declaration had been drafted ahead of Sunday’s emergency meeting of ten EU leaders, with Germany and France hoping for a swift deal that could be approved at a full EU summit at the end of next week.
It contained key elements Ms Merkel needs to placate her rebellious coalition partner, the Bavaria-based Christian Social Union and its head, Horst Seehofer, who is also Germany's interior minister.
Italy objected to provisions that said asylum seekers would have to be returned to the EU country they had first logged their claim in, which often means Italy.
Italy has taken in some 650,000 boat migrants over the past five years, stoking anti-immigration sentiment in the country and fueling the rise of the far-right League, which forged a coalition government this month.
Mr Conte, who had threatened not to go to Brussels on Sunday unless the draft was amended, spoke to Ms Merkel yesterday.
"The chancellor clarified that there had been a 'misunderstanding'. The draft text released yesterday will be shelved," Mr Conte wrote on Facebook, adding that he would now go to Brussels at the weekend.
Germany played down the dispute. "We are in constructive talks with Italy. The meeting on Sunday has only preparatory character," a German government source said.
Unless all EU states agree at their summit on 28-29 June to share out asylum seekers more evenly, Mr Seehofer has threatened to introduce an entry ban on the German border for all those who have already registered for asylum elsewhere.
Ms Merkel opposes that idea as it would require rigid checks on the EU's mostly open internal borders.
Many would see such checks as reversing a key success story of European integration.
Hence, she asked other EU states to hold extra talks this Sunday and agree to do more on migration in the hope that would be enough to convince Mr Seehofer not to go it alone.
