At least eight South African companies have been invaded by self-styled war veterans in Zimbabwe, the department of foreign affairs said on Thursday.
South Africans have been assaulted and kidnapped in the process, said the department's chief director for southern Africa, Dr Pandelani Matoma, at a news conference in Pretoria.
No serious injuries were reported and the kidnap victims were released after ransom was paid, she said.
Director general Sipho Pityana said the South African government had expressed its serious concern to Zimbabwean High Commissioner Simon Moyo.
It had also instructed the South African High Commissioner in Harare to approach the government of President Robert Mugabe. - Sapa