The Goodman Gallery was expected to proceed with an appeal against the Film and Publications Board's (FPB) classification of "The Spear" painting on Monday.
The gallery's lawyers contend that the classification of the artwork was "impermissible and unsustainable".
The Spear, painted by Cape Town-based artist Brett Murray, depicted President Jacob Zuma with his genitals exposed.
The FPB classified the painting with a rating of 16N in July. This meant children under the age of 16 should not have access to the painting because it displays nudity.
The FPB ruled that its classification committee had the necessary jurisdiction to classify the painting, even though it had since been defaced.
The lawyers argued that the FPB had no jurisdiction to classify an original artwork that had been defaced and removed from public exhibition.
"It (FPB) had no jurisdiction to classify the online publication of the electronic image on the Goodman Gallery's website, because there had been no complaint to it in this regard."
The gallery contended that the board did not have jurisdiction to classify an image of the painting on the City Press website, given that the newspaper was subject to the bona fide newspaper exception.
In the event that the classification committee had jurisdiction, it was required to afford a hearing in some form to other publishers of the image.
"We submit that the appeal must be upheld on the basis that the decision of the classification committee was incorrect on its merits."
The committee erred in its treatment of the evidence before it, including in relation to what it considered to be "common cause".
It relied on the concerns of "sensitive adults" when it had no jurisdiction to do so.
The lawyers said the committee failed to recognise that the portrait did not in any event infringe on any person's right to have his or her dignity respected.