The meeting was abandoned after the fall which occurred in the second race of the day.

Ricky Blewitt, Michael Gray and Hackett all came off in an 800m-race with Hackett's condition causing the most concern.

Racing NSW provided an update on Saturday afternoon with Hackett unconscious with family by his side.

Racing NSW chief steward Marc Van Gestel had earlier said Hackett had been airlifted to Sydney.

"Ricky Blewitt will also be airlifted to a Sydney hospital. He is conscious but is complaining of soreness in his back and there are concerns of possible internal injuries," Van Gestel said.

"Michael Gray has gone to Dubbo hospital with a collarbone issue.

"Michael Hackett remains our biggest concern."

Blewitt has suspected abdominal injuries, as well as spinal and back injuries, and also has family with him at Westmead.

Gray has a fractured clavicle and has been undergoing other scans on his head and neck.

All three are regulars on the picnic circuit while Parkes-based Hackett also regularly rides at TAB meetings around the region.

Hackett was riding the Rodney Robb-trained Another Plan in the race at Tomingley, while Blewitt was aboard George Wright Jnr's Run The Red and Gray was riding Sikum for Sharon Jeffries.

All three horses reportedly suffered no significant injuries but that is yet to be confirmed.