The joy of witnessing Winx stride towards equine immortality turned to concern for racegoers at Randwick as the Sydney Cup was called off after fears two fallen riders and a stricken horse were in further jeopardy.

Racing NSW stewards made the decision to abandon the $2 million staying feature after Almoonqith and Who Shot Thebarman collided on the turn leading out of home straight.

Almoonqith, ridden by James Doyle, managed to get back to his feet while Who Shot Thebarman continued to chase the field after unseating Blake Shinn.

Both jockeys avoided serious injury but Almoonqith was euthanised on the track.

While some jockeys in the 14-horse field realised the race had been called off, Corey Brown was unaware and thought he had won aboard Europe-based Godolphin runner Polarisation.

Brown disagreed with the stewards' decision, believing Shinn, Doyle and Almoonqith were in no further danger.

He said he was aware a pony rider was yelling as he rode past but thought that was to alert jockeys to Who Shot Thebarman - not about Almoonqith's predicament.

"I already knew because I heard (race caller) Darren Flindell say that one's broken down after the winning post.

"I just carried on and kept looking up thinking if something's coming head on it's a different story."

Brown claimed jockeys would have had ample time to avoid Almoonqith while Shinn and Doyle were already out of danger.

"I've pulled up to a trot by the time I've got to (Almoonqith), and I won the race."

Chief steward Marc Van Gestel justified the decision on safety grounds.

"The stewards were concerned as for the safety of two riders and that Almoonqith had the potential to get up and run back towards the field," he said.

Although the siren was activated and the clerk of the course and barrier staff tried to tell riders the race was over, Van Gestel said it was unfortunate the message did not get through to the entire field.

Polarisation was followed to the post by Chance To Dance and Goldolphin's other visitor, Penglai Pavilion.

Tommy Berry, who rode locally trained Godolphin hope Tally, said only half the field heard the warning from the clerk of the course.

Berry was aware of Brown's disappointment.

"There's plenty of maybes. But safety's first and it hasn't (gone ahead). There's no point dwelling on it now."

Jay Ford (Mister Impatience) heard the warning and understood the decision to call the race off.

"My first thoughts were to pull up because there were horses or jockeys lying on the track."