Favourite Admire Rakti and Araldo have both died after the Melbourne Cup, adding a sad postscript to Australia's greatest race.

A distressed Admire Rakti collapsed and died in his stall following the race while Araldo was euthanised after breaking his leg in kicking a fence.

As the connections of Protectionist celebrated Germany's first victory in the Cup, Admire Rakti trailed in more than 200 metres behind him, clearly distressed.

The Japanese stallion was trying to match a modern weight-carrying record of 58.5kg in one of the fastest Melbourne Cups ever run.

Sent out as a strong $5.50 favourite, Admire Rakti vied for the lead with My Ambivalent for much of the race.

Jockey Zac Purton, triumphant aboard him in the Caulfield Cup last month, was convinced he was going to repeat that performance.

"The whole way through the run I thought I'd win. I didn't think they'd beat me from where I was," he said.

But with 800 metres to go the horse was not responding and Purton began to have suspicions all was not well.

"I didn't know it was as bad as it was," he said.

As they approached the home turn Admire Rakti was clearly under pressure and then dropped sharply back through the field.

Purton eased him down and virtually walked him over the line, 25 lengths behind the second-last horse, 200-1 outsider Mr O'Ceirin.

He dismounted and as Admire Rakti reached the tie-up stalls he collapsed. Vets pronounced him dead soon after.

"I'm just shattered," Purton said.

"He gave me such a great thrill there at Caulfield. They don't deserve this."

He said the owner Riichi Kondo was also very distraught.

Chief steward Terry Bailey said Racing Victoria vets would conduct an autopsy.

"It's a shame. We had such a nice, clean-run Melbourne Cup," Bailey said.

It is the second consecutive year in which a horse has died in the Cup.

French mare Verema was put down after snapping a canon bone during the 2013 race.

In another post-race incident, seventh-placed Araldo was spooked by a spectator waving a flag and kicked out at a fence when returning to the mounting yard.

Scans later revealed the horse had broken the pastern in his right hind leg, and the injury was severe enough to have the animal euthanised.

It's so sad to hear that Araldo has been euthanized. The injury was too severe. It was a freak accident that claimed him. — Richard Freedman (@R1CHARDFREEDMAN) November 4, 2014

The RSPCA said the deaths were a stark reminder of the risks to racehorses.

"Sadly, injury and death are the price some horses pay for our entertainment in a sport that puts intense pressure on animals to perform to the limits of their endurance."

Coalition for the Protection of Racehorses spokesman Ward Young said about 125 horses have died during or shortly after Australian races in the past year.

"These events are more common then we would like to believe," he told AAP.

FINAL FIELD

1. PROTECTIONIST Trainer: Andreas Wohler (Ger) Jockey: Ryan Moore

2. RED CADEAUX T: Ed Dunlop (UK) J: Gerald Mosse

3. WHO SHOT THEBARMAN T: Chris Waller J: Glen Boss

4. SIGNOFF T: Darren Weir J: Joao Moreira

5. WILLING FOE T: Saeed Bin Suroor (UK) J: James McDonald

6. PRECEDENCE T: Bart & James Cummings J: Michael Rodd

7. ARALDO T: Michael Moroney J: Dwayne Dunn

8. AU REVOIR T: Andre Fabre (Fra) J: Glyn Schofield

9. SEISMOS T: Marco Botti (UK) J: Craig Newitt

10. FAWKNER T: Robert Hickmott J: Nicholas Hall

11. OPINION T: Chris Waller J: Tye Angland

12. GATEWOOD T: John Gosden (UK) J: William Buick

13. LUCIA VALENTINA T: Kris Lees J: Kerrin McEvoy

14. MUTUAL REGARD T: Johnny Murtagh (Ire) J: Damien Oliver

15. BRAMBLES T: Peter Moody J: Luke Nolen

16. UNCHAIN MY HEART T: David Hayes

17. MY AMBIVALENT T: Roger Varian (UK) J: Andrea Atzeni

18. JUNOOB T: Chris Waller J: Hugh Bowman

19. LIDARI T: Peter Moody J: Ben Melham

20. ROYAL DIAMOND T: Johnny Murtagh (Ire) J: Steven Arnold

21. MR O’CEIRIN T: Ciaron Maher J: Chad Schofield

22. ADMIRE RAKTI T: Tomoyuki Umeda (Jap) J: Zac Purton

(Scratched) SEA MOON T: Robert Hickmott J: Tommy Berry

(Scratched) CAVALRYMAN T: Saeed Bin Suoor (UK) J: Craig Williams