Migrants will be grilled in face-to-face interviews with European Union asylum officers before Greek judges rule on any appeals in rapid-fire hearings.
Any economic migrants believed to be at risk of fleeing will be detained on the Greek islands.
The process, which aims to stop illegal migrant crossings into Europe, will involve chartering ferries to send both economic migrants and refugees back to Turkey.
The controversial deal with Turkey will see migrants sent back to Turkish territory for €6billion (£5bn) in aid and visa-free travel from June.
Thousands of refugees have drowned making the perilous journey to Europe
Mrs Merkel insisted Ankara’s bid to eventually join the 28-nation club was “not on the agenda now”.
Many of the deal’s critics have said the proposal between Turkey and the EU will be struck down in the courts because it violates international laws on asylum seekers.
The German Chancellor said Turkey’s EU bid was not yet on the agenda
However, Turkey has not signed the Geneva convention on refugee rights and currently deports some Afghans and Iraqis back to their war-torn countries in a move that is strictly forbidden under EU law.
As the civil war in Syria enters its sixth year, EU officials are expecting another surge in migrants making the perilous journey to Europe this summer as temperatures begin to rise.
However, EU leaders have already declared that the Balkan route is closed for good.
The plan aims to stop migrants from making dangerous crossings across sea to Europe
“The EU summit today and on Friday will determine whether we can reach an agreement that could give us, for the first time, a real chance at a sustainable and pan-European solution to the refugee crisis.”
Mrs Merkel, who adopted an open-door immigration in Germany last year, has backtracked on her stance since on the face of domestic opposition
