Du Plessis, who was fined his entire fee for the match in Hobart, was cleared to play in the third Test in Adelaide and scored a defiant century on Thursday's opening day after walking to the wicket to a chorus of derision from the crowd.
Cricket South Africa said in a statement on Thursday he would appeal the decision, which prompted the ICC to respond before the second day's play in Adelaide.
“The ICC is disappointed that Faf du Plessis has chosen not to accept the findings of Match Referee Andy Pycroft and will instead exercise his right to appeal,” the world governing body said in a statement.
“A Judicial Commissioner will now be appointed to hear the appeal at the earliest opportunity.”
The 32-year-old, standing in for injured regular captain AB de Villiers, was charged after television footage showed him applying saliva to the ball while sucking on a sweet.
The ICC said on Friday the action breached the rules of cricket in relation to applying a foreign substance to the ball.
“The ICC understands that to include, but is not limited to, sunscreen, lip ice and residue from sweets,” it said in the statement.
“The ICC does not wish to prevent players from using these substances for legitimate purposes, however, any deliberate attempt to apply such substances to the ball, as was the case here, will not be acceptable.”
Du Plessis had earlier denied cheating and said he had been made a “scapegoat”.
“I still completely disagree with (the verdict). I felt like I've done nothing wrong,” he said before the third test.
“It's not like I was trying to cheat or anything, I was shining the ball. It's something that all cricketers do.”
ReutersThe International Cricket Council (ICC) have expressed disappointment at South Africa captain Faf du Plessis's decision to lodge an appeal after he was found guilty of a ball-tampering.
Original source: ICC disappointed at Faf’s appeal