Cape Town - The South African Rugby Union (SARU) wants the International Rugby Board (IRB) to explain how a below-par referee was allowed to take charge of the Springboks' Test against the All Blacks in Auckland over the weekend.As it happened: All Blacks v SpringboksRatings: How the Boks rated in AucklandFrench referee Romain Poite came under fire for a series of blunders in the All Blacks' controversial 29-15 Rugby Championship victory over the Springboks at Eden Park.Much to the ire of the Springboks' fans, Poite showed hooker Bismarck du Plessis a yellow card in the 16th minute of the Test for a perfectly legal tackle on All Black flyhalf Dan Carter.Poite then showed Du Plessis a second yellow - and a subsequent red card - for leading with an elbow which connected with the throat of All Blacks flank Liam Messam.The IRB responded on Sunday by admitting Poite had made a mistake."Just as players and coaches make mistakes, the decision was an unfortunate case of human error by the match officials, who, having reviewed the match, fully recognise and accept that they made a mistake in the application of law," the statement read."All match official performances are thoroughly reviewed and assessed by the IRB and are considered when appointments are made for future Test matches."However, SARU wants to know why a referee of such calibre was allowed to officiate in the first place.SARU vice-president, Mark Alexander, told the Beeld website that only the best referees should be considered when the world's top teams clash."The matter will be taken further with the IRB, especially now that they have apologised. We have to find out why things could have turned out so wrong with the decisions," said Alexander.Alexander also said that it is "unacceptable" that such a poor decision was made when the top two teams in the world meet in front of a packed house with millions of fans watching.