Reports coming from South Africa say Zimbabweans are among hundreds of illegal immigrants from across Africa arrested in a crackdown that started Monday.
There are conflicting reports regarding the destination of those that have been arrested, with some saying the South African authorities were deporting them.
Others say that they were still being held at the notorious Lindela Detention facility awaiting deportation.
A Zim journalist based in Cape Town, the epicentre of the operation, said the city's streets were deserted following the combined campaign by South African police and immigration officials.
He said the operation began Monday but intensified Thursday, and noted that only illegal immigrants of African origin were being targeted while those from Asia and Europe were spared.
Nkosiyami Ndlovu, an official from the newly-formed Zim Workers Union in SA, said they had received reports that many undocumented Zimbabweans had been arrested in Khayelitsha, in the Cape Province.
"We are worried about these developments knowing the situation that awaits Zimbabweans back home. We will continue to engage the South African government to grant Zimbabweans legal stay in the country."
Ndlovu said it is not clear what has triggered South Africa's latest crackdown on foreigners but said the Zim community will continue to lobby for leniency for those without permits and for the renewal of permits.
The South African government has said it will announce its decision on permit renewals in August. Initially it had said Zimbabweans whose permits expire in November will have to travel to their home country to get them renewed.
However many Zimbabweans fear that this could be a trap and argue that most of them are refugees who should not be compelled to return to a country from which they fled persecution.