Craig Williams has failed in his appeal against a careless riding suspension and will miss the ride on Hauraki in the Cox Plate.
Williams needed four meetings shaved off his 12 meeting-ban to ride in the Cox Plate after he was found guilty of causing interference in Saturday's Caulfield Cup.
Dwayne Dunn will now ride Hauraki for Godolphin in Saturday's weight-for-age championship at Moonee Valley with the Epsom Handicap winner an $18 chance.