Kiwi expat Jason Collett will undergo shoulder surgery after fracturing his clavicle in a race day fall at Warwick Farm. 

Racing NSW stewards confirmed the injury late on Wednesday night and the top jockey is expected to go under the knife on Thursday. 

“Jason has a fractured clavicle that requires surgery by (Racing NSW doctor) Dr Duckworth tomorrow,” Racing NSW said in a statement. 

Collett, who celebrated his fourth Group One win aboard Montefilia in the Gr.1 Ranvet Stakes (2000m) at Rosehill on Saturday, was riding the Matthew Smith-trained Flambeur in the fourth race at Warwick Farm on Wednesday when the tiring horse stumbled and fell near the 300m, dislodging him from the saddle. 

He hit the ground heavily and was taken to hospital where the fracture was diagnosed.