"Every month, around 15 000 Zimbabwean nationals are deported from a detention centre located on a military base outside the town of Musina close to the Zimbabwean border," Lawyers for Human Rights (LHR) said in a statement on Monday.
It said detainees were rounded up along the border and in town by police, immigration officials and soldiers, taken to the detention centre and deported.
"This is done without any recourse to due process and the procedures under immigration and refugee legislation. This detention facility is operated by the SA Police Service and not by the Department of Home Affairs, whose responsibility it is to manage immigration.
"People in need of asylum protection risk being returned to face persecution in violation of South African and international law," the organisation said.
In addition, the conditions at this facility were appalling and violated even the minimum standards of detention set by the Department of Home Affairs under the Immigration Act.
LHR will be asking the court for an order