English trainer Ed Dunlop has described the death of Red Cadeaux as his saddest day in racing.

The three-time Melbourne Cup runner-up was euthanised when irreversible complications arose concerning blood flow to his left foreleg which he injured in this year's race.

Racing Victoria said vets at the University of Melbourne Clinic at Werribee advised the problem could not be successfully treated.

"This is my saddest day in racing. Red Cadeaux was a much loved member of our family and my thoughts are with his owner Mr Arculli and my staff, particularly Robin Trevor-Jones and Steve Nicholson, who spent every day caring for this horse," Dunlop said in a statement.

"Unfortunately the complication was irreversible and the decision to euthanise the horse, whilst terribly hard, was made in his best interests.

"Red Cadeaux has given us and the racing public so much joy competing with great distinction across the world. He was an incredibly tough competitor with a wonderful nature and he will be dearly missed by all.

"I want to thank all the vets in Australia, particularly at the University of Melbourne Equine Clinic, that have worked tirelessly on the horse since the race and given him the very best of care.

"On behalf of Mr Arculli and my staff, I also want to thank the Australian public and his racing fans around the world for their wonderful support and well wishes during what has been an incredibly tough time for us all."

Red Cadeaux will be buried at Flemington Racecourse at the wishes of his owner, Hong Kong businessman Ronald Arculli.

"For a race that stops a nation we were lucky to have a horse that touched a nation," Arculli said.

"We will miss Red Cadeaux dearly."

Red Cadeaux's performances endeared him to Australian racegoers who adopted him as one of their own.

RV's head of Equine Welfare and Veterinary Services, Dr Brian Stewart, said everything that could have been done, had been done.

"The loss of any racehorse is a terribly sad time for the connections given the love and care they are afforded. The loss of a crowd favourite such as Red Cadeaux is felt by all within the industry," Stewart said.

"I would also like to pay tribute to Dr Chris Whitton and the team at the University of Melbourne Equine Centre who have done everything in their power to save the horse and have given him the very best of care since he sustained his injury.