Thousands of recognised refugees in Greece face the prospect of being left homeless after their right to stay in temporary accommodation expired on Monday (June 1).
It comes after a new law, passed in November, reduced the period they could be sheltered from six months to just one.
The Emergency Support to Integration and Accommodation (ESTIA) scheme sees them hosted in apartments in Athens.
The UN's refugee agency (UNHCR) told Euronews that at least 8,500 refugees would be affected by the change.
Athens said the move was necessary to alleviate pressure on the more than 32,500 migrants living in squalid camps on the Greek islands.
"It is normal that those who have been in Greece for longer can leave their place," said Manos Logothetis, secretary of the Greek asylum service. "There must be a limit, and the refugees integrate and find a job."
But for Boris Cheshirkov, the UNHCR spokesman in Athens, the move is worrying.
"Refugees will have to leave this form of assistance without effective access to Greek social services," he said. "In theory, they are entitled to assistance but in reality for those who do not speak the language, navigating the Greek bureaucracy can be extremely difficult."
Some people now leaving the housing program are single parents who have been through violence, even torture, who may be traumatized and have not yet learned Greek, he added.
"We need to see credible programs that are effectively allowing people to stand on their own feet before they're leaving on such short notice."
Fears of a humanitarian crisis
Most of the accommodation provided by the scheme is in Athens and evicting so many refugees could trigger a humanitarian crisis in the city.
Greek newspaper Efsyn said it would be "devastating and not just for the refugees".
The ESTIA scheme was created to support migrants who are waiting to get their asylum request examined.
Though the scheme is funded by the EU, it is the Greek government that decides who can access it.
Efsyn accused Greek Immigration Minister Panagiotis Mitarachis of aligning with "xenophobic and extremist groups", adding that the decision was taken only because of "the urgent need of alleviating (migrant pressure) on the islands, where most of his voters are based".
Athens's city council, as well as pro-migrant groups, are working to find new shelters for the refugees as well as to provide them with basic necessities.
"UNHCR has continuously raised its concerns that recognized refugees are expected to leave assistance but they do not have effective access to social benefits and support," the UN's refugee agency said in a statement.
"Many of those affected are vulnerable, including but not only most staying in ESTIA accommodation. Their effective inclusion in national systems offering services and for cash or in-kind support has not been possible so far. The situation is aggravated by the COVID-19 pandemic.
"The risk of tensions are also increasing, and many people may be unable or unwilling to comply with the decision to leave their accommodation.
"UNHCR has been urging a phased approach for refugees to leave assistance and a higher threshold to support vulnerable people who cannot leave their assistance at this stage in combination with other quick impact interventions to cover their basic needs."