Foreign nationals in South Africa suffer "routine" xenophobic violence and live in constant fear of being targeted, a new report by Human Rights Watch (HRW) said on Thursday.

Foreign workers from across Africa and Asia emigrate to South Africa for economic opportunities but compete against locals for jobs, which are few and far between as the country's unemployment rate sits above 30%.

HRW said in a 64-page report foreigners are scapegoated for economic insecurity in one of the world's most unequal societies.

The right's group relayed testimonies by over 50 African and Asian nationals of "routine" and "sometimes lethal" xenophobia.

In September last year, businesses were ransacked in a bout of xenophobic violence. Clashes left at least 12 people dead, of whom 10 were South African, according to the government.

One Bangladeshi shop owner told HRW he had to stand guard for three days without sleep until police arrived.

Other foreigners said they sometimes suffered verbal and physical harassment in their daily interactions with locals.

A common insult in South Africa is "kwerekwere", a derogatory word for "foreigner".

The report said last year, a Congolese student was allegedly beaten up by her peers after being elected class monitor at a Cape Town high school.

She was hospitalised for nine months.

'Living in constant fear'

At least 62 people died in xenophobic attacks in 2008, seven were killed in unrest in 2015.

HRW accuses law enforcement officials of being complicit, often operating in "discriminatory" and "abusive ways" towards non-nationals.

It claims foreign-owned businesses are disproportionately targeted by crackdowns on counterfeit goods, and that migrants are arbitrarily detained for allegedly lacking the right documents.

According to the group, police are reluctant to protect immigrants and investigate crimes against foreigners.

The report has called for "more urgent, concrete measures" to protect foreign nationals, claiming a government plan unveiled last year has been "just words on paper" so far.

Author Kristi Ueda condemned the "impunity" that "only emboldens others" and perpetuates violence against foreigners.

"Non-South African nationals have suffered wave after wave of xenophobic violence and live in constant fear of being targeted," said Ueda.

"Government should hold those responsible accountable to the fullest extent of the law."

South Africa's government has yet to respond to the report.

The country attracts people from neighbouring Lesotho, Mozambique and Zimbabwe, who seek better employment prospects.

Others come from even further afield including Congo, Ethiopia, Malawi, Nigeria and South Asia.

South Africa plays hosts to more than 2.2 million foreigners, ranging from political refugees and economic migrants to skilled expatriate workers, according to the last population census in 2011.