Public Order Minister Christos Papoutsis said Wednesday that the leasing of floating detention centers for illegal immigrants is being considered as part of other measures.
"But we must review difficulties ... that include the high cost of the transfer of such a vessel and various docking issues."
The measures are likely to include building a fence on part of the Greek-Turkish border and using old army facilities as detention centers.
The Netherlands began using floating facilities, officially called "detention platforms," in 2007, according to rights group Amnesty International.
The government did not comment on a newspaper report that Greek officials are due to visit to the Netherlands to discuss the feasibility of transferring purpose-built prison ships to Greece.
Greece says about 128,000 immigrants entered the country illegally in 2010 - the highest number in the European Union.
The country's largest civil servant union, Adedy, said Wednesday it would join in a planned rally against the proposed border fence on Jan. 15.
The rally is organized by left-wing protest groups and immigrant organizations.
"We urge the government to take back this plan; it is racist and unacceptable," said protest organizer Petros Constantinou. "Our borders should be open to refugees and the oppressed."
Constantinou urged the government to overhaul strict asylum rules, under which more than 99 percent of all applications for refugee status are currently rejected.
Iranian, Palestinian and Afghan migrants have staged hunger strikes in Greece in recent months, demanding refugee status. They claim to have suffered violence from police and extreme right wing gangs.
The hunger strikers include six Afghans, who have been camped with their lips sewn together alongside families and children as young as two months old outside a university building on a busy central Athens avenue since Nov. 22.
"If there is no response from the government, more of us will sew our lips," said Reza, an Afghan man from the capital Kabul. He did not give his surname.
The 23-year-old, who has lived in Greece for the past six years, said the proposed fence would force migrants desperate to enter the country to seek more hazardous ways in - including sea crossings in rickety boats that have drowned dozens in recent years.
"And when somebody reaches that extreme point," he said, "it means they are risking their lives."