The footage, first aired by South African outlet Independent Media, 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 round 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 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.
Shortly after the footage emerged, a Cricket Australia statement said: “CA is aware of reports of an incident between players in Durban. CA is working to establish the facts of what occurred and will not be commenting until this has been done.”
There has yet to be a response from Cricket South Africa.
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.
“Obviously it was a huge wicket. You put a lot of planning into how you’re going to bowl to someone like AB de Villiers, so to have him run out for zero is – I think that gets everyone a little bit excited,” Paine said after the day’s play. “The boys were certainly pumped up to see him going back. We think he’s their best player, to have him back in the sheds for zero was a huge confidence boost for us. But we also know how good the rest of their side is.”