Published: 2021-02-23 11:28:18 BdST
The 1,200 detainees are scheduled to leave on Tuesday afternoon in three navy ships sent by Myanmar's military, which seized power in a Feb 1 coup, sparking weeks of protests from pro-democracy activists.
Refugee groups say asylum seekers from the minority Chin, Kachin and non-Rohingya Muslim communities fleeing conflict and persecution at home are among those being deported.
Malaysia has said it would not deport Rohingya Muslims or refugees registered with the United Nations High Commissioner for Refugees (UNHCR).
The UN refugee agency has said there are at least six people registered with it that are also set to be deported and that there could be more. It has not been allowed access to the deportees.
Buses and immigration department trucks were seen taking the detainees to the western Malaysian port of Lumut, where the Myanmar ships are docked at a naval base.
Rights groups Amnesty International and Asylum Access sought a court order on Monday to stop the deportation, saying three people registered with UNHCR and 17 minors who have at least one parent in Malaysia were among the deportees.
"If Malaysia insists on sending back the 1,200 individuals, it would be responsible for putting them at risk of further persecution, violence and even death," Katrina Maliamauv, Amnesty Malaysia director, said on Monday.
The court is set to hear the request at noon (0400 GMT).
Malaysia has not responded publicly to critics or Reuters queries over the deportation of the asylum seekers and those registered with the UNHCR.
Concerns over deportation of unregistered asylum-seekers also persist as the UNHCR has not been allowed to interview detainees for over a year to verify their status, amid a crackdown on undocumented migrants in Malaysia.
The U.S. and other Western missions have been trying to dissuade Malaysia from proceeding with the deportation and urged the government to allow the UNHCR to interview the detainees. They also say Malaysia is legitimising the military government by cooperating with the junta.