Greece on Wednesday carried out the first relocation of asylum seekers from its territory to Luxembourg, part of an EU-approved plan to ease the burden on border nations inundated by this year's influx of hundreds of thousands of refugees.
Six families from Syria and Iraq were being relocated from Athens, among the first under a 780-million-euro, two-year scheme funded by the European Union.
"Thirty in the face of thousands who have fled their homes in Syria and Iraq is a drop in the ocean," Tsipras said.
"But we hope that this becomes a stream, and then a river of humanity and shared responsibility, because these are the principles upon which the European Union was built."
More than 580,000 refugees have entered Greece through its long sea border with Turkey this year.
In September, the EU approved the transfer of about 160,000 asylum seekers from member states directly affected by the crisis.