World Rugby have replaced Marius van der Westhuizen as assistant referee for Saturday's Six Nations meeting of England and Ireland after the South African attended one of the hosts' training sessions hosts earlier this week.
World Rugby said that although it was happy for match officials to attend team training, it was not appropriate for them to do so if they would soon be officiating the same team.
Van der Westhuizen will be replaced on the touchline by veteran Welsh whistler Nigel Owens.
World Rugby said that Van der Westhuizen "is an outstanding talent with a big international future and both he and his employer SARU fully support the decision."
Speaking prior to the decision, Ireland head coach Joe Schmidt expressed surprise at Van der Westhuizen attending England training but said he had full confidence in his impartiality.
"That is a bit of a surprise," said Schmidt. "I'm sure in retrospect people are probably thinking it's not the best thing to do.
"I know Marius and I would have no hesitation in standing by his integrity."
World Rugby statement:
World Rugby has confirmed that Marius van der Westhuizen will be replaced by Nigel Owens as Assistant Referee 2 for the Natwest 6 nations match between England and Ireland at Twickenham on Saturday.
The decision follows Marius’ attendance at an England training session this week. While greater dialogue and collaboration between match officials and teams (including attending team training on request) has been agreed by World Rugby and the teams, Marius should not have been involved given that he was a member of the match official team for the weekend’s match.
World Rugby takes responsibility for this oversight and has taken the proactive decision to stand Marius down to avoid any additional unfair and unnecessary conjecture. Marius is an outstanding talent with a big international future and both he and his employer SARU fully support the decision.
World Rugby has also clarified with teams that, in addition to the regular pre-match coach and referee meetings, senior elite teams will continue to have the opportunity to request that a member of the high-performance match official panel attends training providing that the individual is not a member of the match official team officiating that team at a later date within the current competition or test window.
Follow England v Ireland on Saturday (KO 2.45pm) via the live blog on RTÉ.ie/Sport and the News Now App, or listen live on RTÉ Radio 1, with commentary from Michael Corcoran and Donal Lenihan.