Classifying "The Spear" painting by Brett Murray as not suitable for people under the age of 16 was the right thing to do, the SA Communist Party said on Friday.

"The decision by the Films and Publications Board (FPB) ... affirms the fact that we are not a pornographic society, but a society with moral values," SACP spokesman Malesela Maleka said in a statement.

However, the SACP was concerned about the board's reluctance to report people violating the classification.

"While we agree that we need to use this unfortunate incident for broader educational awareness, nevertheless those who violate this classification must be reported to the police and be charged accordingly."

The FPB announced its decision to give the painting a 16N rating in Johannesburg earlier in the day.

This means children under the age of 16 should not have access to the artwork, because it displays nudity.

The painting, which was vandalised last Tuesday, depicted President Jacob Zuma with exposed genitals.

FPB CEO Yoliswa Makhasi said the board understood the image of the painting had gone viral, but urged youths to delete copies of it.

"We don't seek to punish people in our day-to-day work," she said.

The board said it would not report people to police, but would work with service providers to limit access to the image.

When asked how this image differed from other nude artworks, FPB chief operations officer Mmapula Fisha said Murray's painting was not just a piece of nude art.

"The artwork has forced society to revisit its painful history."

The classification had to balance this and artistic merit.

Chairwoman Thoko Mpumlwana reiterated that the board could not hear a classification complaint against the City Press, only the Press Ombudsman could.

City Press published a photograph of the painting on its website. It removed the image on Monday, following an outcry and calls for a boycott.

Mpumlwana said if any of the affected parties were dissatisfied with the decision they could appeal to the FPB's appeal tribunal within 30 days.