A group of migrants has lived at a youth centre north of Tunis after being evacuated from the Choucha refugee camp. AFP
The 25 men from Egypt, Niger, Nigeria and Sudan had sought asylum in Tunisia after fleeing violence in neighbouring Libya in 2011, but their requests were denied, said Romdhane Ben Amor of the Tunisian Forum for Social and Economic Rights (FTDES).
He said their repatriation would "put their lives at risk".
The Tunisian cabinet approved on Friday the expulsion "as soon as possible of a group of migrants residing illegally in Tunisia", the government said in a statement.
Since 2017, the migrants have been living in a youth centre in Marsa, a suburb of the capital Tunis, "hindering its activities" by "categorically refusing to leave", it added.
The group, aged 30 to 32, moved to the youth centre after being evacuated from the Choucha refugee camp in southern Tunisia, FTDES said in statement Sunday, expressing its "indignation at the repressive and inhumane decision by the government".
The FTDES "warns against any attempts to forcefully impose a solution on a vulnerable group that has suffered for more than 10 years", it said.
It urged civil society groups to mobilise against "discriminatory policies" that affect undocumented migrants, who have also been "neglected by United Nations agencies and the European Union".
The UN refugee agency UNHCR opened the Choucha camp in early 2011 to shelter those fleeing conflict amid the fall of Libya's former leader Moamer Kadhafi.
At its peak, Choucha hosted around 18,000 refugees.
But in 2013, UNHCR decided the close the camp while hundreds of its remaining residents were awaiting resettlement in third countries.
Some have left Tunisia, while others were offered accommodations in cities in the North African nation.
Several dozen migrants refused to leave Choucha, demanding their asylum requests be granted. They were finally removed in 2017.