The Zimbabweans were accused of stealing jobs
The UN has condemned attacks against Zimbabweans seeking work in South African vineyards, which it says have driven 3,000 people from their homes.
Local farm workers accused the Zimbabweans near Cape Town of stealing their jobs by accepting lower wages.
South Africa saw an outbreak of xenophobic violence in May last year, when Zimbabwean refugees and asylum seekers were attacked.
More than 60 people died in the waves of mob violence.
The UN refugee agency said those displaced in the latest unrest were living in tents in a sports field north-east of Cape Town.
On Friday, police said they had arrested 22 people in the informal settlement of De Doorns in Western Cape for allegedly attacking foreigners earlier this week, South African Press Association reports.
The trouble broke out when South African farm labourers were angered at reports that the farmers were employing migrant workers at lower wages.
"They started to shout at us saying that we had to go back to Zimbabwe," one migrant worker told the BBC.
"After that they started to break our houses. We phoned the police but the police didn't take action. They just stood there as people broke our houses and they stole our things."
Correspondents say South Africa is keen to show the world that poverty and crime is under control in preparation for next year's World Cup.
But for millions of South Africans the reality is very bleak.
This year there have been township riots by residents unhappy at the lack of decent housing and basic services, such as water and electricity.