Clarry Conners has been taken to hospital after he was kicked in the face by a horse at Hawkesbury racecourse.

The trainer suffered swelling to his right cheek and eye, as well as bleeding to his mouth but did not lose consciousness.

The incident happened in the mounting enclosure before the first race on Thursday.

Conners had legged jockey Jim Cassidy aboard his runner Yesterjoy when he was struck by rival Thunder Lady.

He was attended by paramedics at the scene before being taken to Nepean Hospital and was in good spirits, according to Racing NSW steward Chris Polglase.

The first race was delayed while officials waited for a second ambulance to arrive on course to take Conners to hospital.

Thunder Lady finished second while Yesterjoy, a daughter of top racemare Tuesday Joy, did little to ease Conners's pain, finishing sixth.