The International Rugby Board (IRB)on Thursday said it would appeal the decision to clear Australia captain James Horwill of stamping on British and Irish Lions lock Alun Wyn Jones.
Horwill was cited for stamping during the first Test between Australia and the Lions in Brisbane on June 22, which the visitors won 23-21.
But the Australia Rugby Union (ARU) assessed after a disciplinary hearing that, on the balance of probabilities, there was no act of intentional foul play.
As the Lions tour falls under the IRB's remit, the Dublin-based world governing body said it had a right to appeal any decision from the matches.
"The IRB received the full written decision on Monday June 24 and following a detailed review of the evidence and the written decision (as it does for all Tests under its jurisdiction) has notified the ARU within the 72 permissible hours that it will appeal the case," it said in a statement.
"The appeal will be heard by Graeme Mew (Canada) following the second Test between Australia and the British & Irish Lions. Horwill is free to play pending the outcome of the appeal."
The ARU said in a response that it was "surprised and disappointed" by the IRB announcement about the Wallabies skipper, saying it was the first time the federation had exercised its right to set aside a "not guilty" verdict.
"This is an unprecedented step taken by the IRB in what is the most important Rugby event staged in Australia since the 2003 Rugby World Cup, said ARU chief executive Bill Pulver.
"While we respect the right of the IRB to intervene, we also respect the knowledge and experience of appointed -- and independent -- Judicial Officers, and their expertise to consider evidence and reach sound findings.
"James Horwill was cleared of the stamping charge as per the IRB's established judicial process. We are surprised and disappointed that the finding of Mr Hampton is now not only under question but deemed to be 'erroneous'."
The appeal had the potential to cause "serious disruption" to the Wallabies, Pulver added, insisting that they had followed IRB due process to the letter.