Pre-race favorite Admire Rakti collapsed and died after finishing last in the Melbourne Cup at Flemington Racecourse on Tuesday.
The Japanese-trained horse, which won the Caulfield Cup last month, started the race as 5-1 favorite but faded towards the end of the grueling 3200 meter handicap.
"The favorite Admire Rakti on return to the stalls after the race has collapsed and died," Racing Victoria chief steward Terry Bailey said.
"Our vets are on hand and the horse will undergo an autopsy. We will have to await those results for the cause of the death."