Some 62 migrants have been killed and tens of thousands forced from their homes around the country. The violence, which has subsided, targeted mostly Zimbabweans and Mozambicans.

The government plans to move thousands of displaced people to various camps around the Gauteng province, where the violence first broke out.

"Oxfam is concerned that minimum standards of humanitarian assistance and protection have not been met. Adequate water, sanitation, and security facilities should have been in place ahead of relocations," the agency said in a statement.

Oxfam said one of the camps did not have sufficient toilets and a water tank did not have taps, posing a health risk.

Radio 702 reported that residents at Midrand, where the government was setting up a shelter for displaced residents hurled insults at a senior official who came to address them.

The residents were concerned about crime and the value of their homes if the temporary shelter is set up, Radio 702 said.

Analysts say competition for housing and jobs combined with soaring food and fuel prices raised tensions that led to the riots. Unemployment in South Africa hovers around 24 percent.