Groups of blind people and their guide dogs protested outside Nando's stores in Johannesburg and Cape Town on Monday as staff from the outlets stood by offering them and passers-by free samples of chicken.
The protesters were objecting to the latest Nando's television advert, which shows an elderly woman being deliberately led into a pole by her guide dog so that it can get to the chicken she has just bought from a Nando's outlet.
The lunch-time protests were organised by the SA Guide Dogs Association for the Blind, who are objecting to the advert, saying it makes light of blind people's disabilities.
Many of the protesters felt, however, that the advert was more offensive to the reputation of guide dogs.
One guide dog owner, Albert Bezuidenhout, said: "One of the first things they learn is to always protect the person they are leading."
The association is demanding a national apology from the chicken outlet, which is known for its controversial advertising campaigns.
Julian Ribeiro, account director for TBWA Hunt Lascaris, said: "We took the same approach with this ad as with others of this nature which look at human truths, the holy cows of society, and subjects and issues that are generally taboo, and make light of them."
Ribeiro added that the complaints were coming from only one source.
"The ad is genuinely funny. There was never any intention to discriminate against anyone, there was never any intention to hurt anyone," he said.
Nando's has decided it will not withdraw the advert, for the time being.
Nicky Papachristo, regional marketing manager for the chicken outlet, said: "The ad was not designed to be offensive. It was done in a very slapstick way."
She said they had consulted several blind people during the making of the advert, who had not found it offensive.
In addition, they had used a guide dog from a blind person who did not object to the advert.
The Advertising Standards Authority has called on Nando's and its advertising agency to respond to the complaints.
No further protests have been planned. According to the guide dog association's executive director, Ken Lord, more protests would just generate free publicity for Nando's.