The withdrawal of an advertisement depicting President Jacob Zuma and his family eating fish and chips may constitute censorship, the Freedom of Expression Institute (FXI) said on Wednesday.
"The FXI is of the opinion that this action by the SABC may constitute censorship, in the absence of an explanation as to why the advert was banned," it said in a statement.
"This is especially concerning as this is not the first time that the SABC has banned an advert for one reason or the other."
The FXI said the public broadcaster should demonstrate that the decision to pull the ad was "neither arbitrary not whimsical" and was done in line with existing policy.
The SABC said on Tuesday that the commercial was not aired because it implied presidential endorsement of the product.
"We are of the view that the advert implied an endorsement of the product sold by the Fish and Chip Company," spokesperson Kaizer Kganyago said in a statement.
He said the SABC was concerned about media claims that it had banned the advertisement.
"The SABC reserves the right to exercise editorial control over all content, as per our trading terms, licence conditions, and public broadcast mandate."
Kganyago said the advert was not submitted to the SABC in time for it to examine the quality and other technical aspects.