CA had said early on Monday morning - the fifth day of the Test - that it would investigate the incident, which was caught on CCTV and first aired by South African outlet Independent Media. "The incident was discussed between the two team managers and the match referee last night and it is now in the hands of the on field umpires and the match referee," CA said later on Monday. "Both teams were reminded by the match referee of the spirit in which the game should be played."
The footage shows Warner being moved away from the incident by team-mates, including captain Steven Smith, after walking up the steps during the tea interval on the fourth day.
Australia had managed just one wicket between lunch and tea with de Kock and Aiden Markram forging a partnership that would threaten to take South Africa close to their 417-run target before Australia struck back late in the day.
In the video, Warner's anger is directed at de Kock, who is following the Australians up the steps. At the start of the clip, the Australian players first up the stairs are seen peering back over the handrails then Warner emerges around the corner and is already involved in a heated exchange.
He is ushered up the steps by Usman Khawaja but does not immediately enter the away dressing room, even though Tim Paine also urges him to move and go inside. Smith then drags his vice-captain away as de Kock squeezes past into his dressing room. There was no indication from the footage what started the incident.
South Africa team manager Mohammed Moosajee said: "It's rather unfortunate that the incident took place and certainly not in the spirit of the game. The match referee has spoken to us after the day's play. We will await any further communication from the ICC around this incident."
Warner's behaviour came under the spotlight earlier on the fourth day when he ran out AB de Villiers after a mix-up with Markram with him then yelling in Markram's direction during the celebration. Warner was not charged for that incident, but Nathan Lyon was, because the bowler had dropped the ball in de Villiers' vicinity.