Crowds of migrants trying to enter South Africa from neighbouring countries have been swelling at various border posts.
The Kosi Bay post on the border with Mozambique and the Beitbridge post on the border with Zimbabwe are the worst affected.
South Africa Home Affairs Minister, Aaron Motsoaledi, has been quoted by local media as saying a "humanitarian crisis" may be unfolding at Beitbridge post.
Zimbabwean journalist Hopewell Chin'ono has tweeted a video of the crowds of Zimbabweans at the border post:
https://twitter.com/daddyhope/status/1346367042761449472
The long queues at the border posts are linked to a requirement for the migrants to produce a negative Covid-19 test result obtained 72 hours before date of travel, according to the news24 website.
Zimbabwe on Tuesday entered into a second lockdown following a surge in coronavirus infections. Tough restrictions, including closing of border crossings, will be in place for 30 days.