Nigerian government officials are fuming over the treatment dished out to Dr Anderson Anyikwa, who works at a state hospital in Port Elizabeth.
The 38-year-old doctor was denied entry to Cubana Latino Café in Port Elizabeth by staff who, he claims, said Nigerians were not welcome in the establishment because they sold drugs.
Vincent Omeokachie, minister of consular matters at the Nigerian High Commission in Pretoria, this week said he had taken up the matter with South Africa's Department of International Relations and Co-operation.
"We are pursuing the matter to its conclusion. What happened could only happen during the apartheid era. As Nigerians, we can't accept it. It's not only about Dr Anyikwa, it is racial discrimination; we will make sure it doesn't happen to any other foreigner," he said.
The incident, which happened two months ago, is being taken to the Equality Court and is also under investigation by the Human Rights Commission.
Anyikwa has permanent-residence status and has worked for the Department of Health as a senior doctor since 2007.
He met medical colleagues at the restaurant in Summerstrand where he was stopped by a doorman who demanded to know his nationality.
"I was the only one who was asked this question out of the five or six of us. I told the doorman I was from Nigeria. Then he said to me, 'We don't allow Nigerians into our restaurant.'"
Cubana franchise spokesman Lisa Bright was aware of the incident and said they would co-operate if there was a need for any further investigation.
"Basically our doormen abide by the franchise door control. We have a very strict smart-casual dress code and obviously (do not allow in) intoxicated customers.
"We are a multiracial company. We are by no means racist. The franchise has black Zimbabweans and black Congolese guys working there."
Advocate Solomon Moreroa, head of the South African Human Rights Commission in the Eastern Cape, said: "I think it's a question of race. I did some inquiries and it looks like every time you enter that restaurant you're asked where you are from if you are black , If indeed there was discrimination, we will take the matter to the Equality Court."
Anyikwa said he was humiliated as his colleagues tried to explain that he was a medical doctor at the city's Livingston Hospital.
Anyikwa reported the incident at the Humewood police station. Two police members took him back to the restaurant where managers simply pointed to the "right of admission reserved" notice. Police then opened a case of crimen injuria, but later suggested the matter be referred to the Equality Court.
Anyikwa's lawyer, Jacques Ehlers, confirmed that he was preparing to file papers at the Equality Court in Port Elizabeth...
"When Nelson Mandela said, 'South Africa belongs to all who live in it,' he did not exclude residents of Nigerian nationality," said Anyikwa.