“[Head contact] was found to be secondary to the initial shoulder contact and made with much lower force and without the requisite level of ‘danger’ required under World Rugby’s Head Contact Process to make the offending reach the red card threshold,” the committee wrote after reviewing replays and evidence from Mostert.

South Africa are already missing Mostert’s fellow second row Lood de Jager for the meeting with Ireland after De Jager was sent off for a similar incident in the Springboks’ win over France a fortnight ago and banned for the rest of the autumn internationals.

South Africa assistant coach Mzwandile Stick claimed on Monday that his side were being treated unfairly by officials. He also referenced bans given to Makazole Mapimpi and Jan-Hendrik Wessels for incidents on club duty that have kept them out of South Africa’s northern hemisphere tour.

Even without De Jager, South Africa are well stocked at second row.

Jean Kleyn, who made five appearances for Ireland in 2019 after qualifying for them through residency and then reverted back to his home country after a stand-down period, started against Italy, with Leinster’s RG Snyman and Ruan Nortje on the bench.

Eben Etzebeth, a talisman in South Africa’s World Cup wins of 2019 and 2023, was rested for the fixture.