Lesotho says South Africa breached its "free movement" arrangement with the country when authorities instructed 400 Basotho to leave Newcastle in KwaZulu-Natal early last week.

The Lesotho government had to repatriate its nationals amid questions about their status in South Africa.

"Over 400 Basotho were transported to Lesotho by the government of Lesotho following an incident of being chased by the authorities there, in concern about their legality in South Africa," read a statement by Minister in the Prime Minister's Office Limpho Tau.

Tau called it a "traumatising" event that should not have happened because of the two countries' cordial relations. He noted Lesotho's deep concern over the treatment of its citizens while in South Africa, saying the countries had signed bilateral agreements that included free movement.

Tau said Lesotho had reached out to the South African government, and "all will come to light once the talks are being set and agreed upon".

He added that the safety of Lesotho nationals outside the country was one of the country's top priorities.

"One of Lesotho's key points of action for the plight of Basotho is to ensure their freedom while in South Africa and elsewhere by ensuring that they all have proper expected documents," he said.

Lesotho's Disaster Management Authority acting chief executive, Caroline Mahosi, said they would go back for the Basotho nationals who hadn't made it on the first trip. She also promised that those who had already left for Lesotho would be "delivered to their respective homes".

During interviews with SABC News, some of the affected Basotho nationals said they had been banned from South Africa for the next five years.

The deportees were allegedly living and working in South Africa without permits, while others were flagged as overstaying in the country.

Meanwhile, South Africa will resume the deportation of undocumented Zimbabweans living and working in the country as of June next year.

This follows the extension of the window period for Zimbabweans to switch from their discontinued Zimbabwean Exemption Permits (ZEP) to regular visas.

Initially, the deadline had been the end of December 2022, but this was later shifted to June next year.

According to the Zimbabwe National Statistics Agency, South Africa is home to 773 246 Zimbabweans, but independent estimates put the figure at around three-million (more than the entire population of Botswana, which is pegged at 2.3-million, or that of Lesotho at 2.1-million).