The incident occurred during a routine gallop on the course proper, with Hamada sustaining a fracture to his near-hind leg shortly before the winning post.
The five-year-old son of Cape Cross was rushed to the Werribee Vet Hospital but unfortunately could not be saved.
"On vet's advice, the nature of the injury left us no alternative. The kindest course of action was to euthanise the horse," said Appleby.
Earlier report Saturday - Hamada (GB) one of Charlie Appleby's Melbourne Cup hopes, has sustained a serious injury during trackwork at Werribee on Saturday morning.
Hamada was galloping on the course proper at Werribee with another runner from the Appleby stable when the injury occurred shortly before the winning post.
The extent of the injury is not yet confirmed and the lightly-raced Cape Cross five-year-old has been taken to the Werribee Vet Hospital.
"Hamada went lame at exercise and is under veterinary supervision at the moment," Appleby said.
Hamada has won five of seven career starts and arrived in Australia in superb form, having won the Group 2 Geoffrey Freer Stakes at Newbury on August 18.
A Racing Victoria spokesman later also confirmed the injury: "We can confirm that Hamada has sustained an injury during trackwork at Werribee this morning. The horse has received veterinary care and is undergoing x-rays to determine the extent of its injury."