JOHANNESBURG (AFP) - The South African government on Thursday (Feb 23) called for calm after a wave of xenophobic violence in which dozens of shops and houses owned by immigrants have been torched and looted.

Attacks against foreigners and foreign-run businesses have erupted regularly in recent years in South Africa, fuelled by the country's high unemployment levels and dire poverty.

In the last week, more than 20 shops have been targeted in Atteridgeville, outside Pretoria, while residents in Rosettenville, south of Johannesburg, attacked at least 12 houses.

Many locals have alleged that the targets were brothels and drug dens being run by migrants from elsewhere in Africa, including Nigeria and Zimbabwe.

A march protesting against migrants is due to be held in Pretoria on Friday, raising fears of violence in the city centre.

"I wish to appeal to all South Africans to desist from rhetoric or actions that are xenophobic," Home Affairs Minister Malusi Gigaba told a press conference.

"There are renewed incidents of violence against foreign nationals in Rosettenville and Pretoria West," he admitted, blaming a lack of jobs and alleged "drug peddling and prostitution" involving foreigners.

In the Nigerian capital Abuja, about 100 demonstrators gathered outside the offices of two South African companies - telecoms giant MTN and satellite TV provider DSTV - to protest against the violence.

The Nigeria government this week called for the African Union to step in to stop "xenophobic attacks" on its citizens in South Africa, claiming 20 Nigerians were killed last year.

South African authorities dismiss such numbers, saying many violent deaths in the country are due to criminal activity rather than anti-immigrant sentiment.

The UN's International Organisation for Migration (IOM) has said it was "very concerned" about the march on Friday.

"We condemn the attacks, looting and burning of property owned by foreign nationals and call on citizens to refrain from... taking the law into their own hands," it said.

"There is no evidence that foreign nationals are responsible for the rise in crime and unemployment."

Gigaba said that South African authorities were in talks with organisers of Friday's march, and that the police would ensure there was no violence.

The Right2Know civil action group and other campaigns have called for the event to be cancelled.

In 2008, South Africa experienced its worst bout of xenophobic violence, which left 62 people dead.

In 2015, at least seven people died in similar unrest in Johannesburg and Durban as African immigrants were hunted down and attacked by gangs.

On Wednesday, Finance Minister Pravin Gordhan said that 35 per cent of the labour force was unemployed or has given up looking for work.