The incident happened in the closing stages of race 3 at 1.40pm.
"I've never seen anything like it at a racetrack before," Balcolmbe added. "He ran along the outside of the course as the horses charged to the winning post. He even crossed the line himself.
"The guy had been drinking but he wasn't completely legless. He is a bloody idiot."
The groom-to-be - believed to be in his late 20s - has been banned from the course.
Shocked people at the track took to Facebook to share what they had just witnessed.
Kate Goodrich posted: "Did anyone just see that race at Otaki?? See the idiot on the track faceplant on the line!"
The 2100m race wasn't disrupted and was won by Derby Dan.
Meanwhile in Auckland, a transvestite who allegedly stole a wig from a mannequin appeared in court yesterday.
Staff at a Queen St store said the 20-year-old man pinched the blonde wig after staking out the store on Friday.
"He was caught red-handed by one of the customers," a Portmans employee said.
"We chased after him but he was already gone."
She said police caught up with the West Auckland man, who told police he was a prostitute in need of a better appearance. He is yet to plead to the charge.
