Jason Collett has walked away from a heavy fall at Randwick after his mount Prahaar looked set to win before veering to the outside rail.

The David Pfieffer-trained Prahaar was leading the Australian Turf Club Handicap (1000m) when she suddenly changed course approaching the winning post, unseating Collett.

No other runner was involved in the incident and Collett was never in danger of being trampled after landing heavily.

The New Zealander was able to walk unassisted to an ambulance, where he complained of neck pain.

Collett was stood down for the remainder of Wednesday's midweek card.

Prahaar was holding eventual winner Swaffham Bulbeck at bay when she inexplicably headed to the outside rail.

Winning jockey Brenton Avdulla took no satisfaction from the Hawkes Racing-trained gelding breaking his maiden at the third attempt.

"He had a good margin on me, he was probably half a length in front of me so it's a bit of an ill feeling for me," he said.

"I'm pretty close to Jason and it's not ideal when you see any rider go (off).

Click here to view the replay of Race 3 courtesy of Racing NSW.