Passerby rushed to a carriage horse's aid after it took a tumble outside of Central Park Sunday afternoon, witnesses said.

The white Percheron horse was trotting with four people in tow when it stumbled to the ground near Grand Army Plaza at 59th St. and Fifth Ave. around 4:30 p.m.

The three adults and one child in the carriage were not injured, a spokesman for the American Society for the Prevention of Cruelty to Animals said.

"No horse collapsed," a spokesman for the Horse and Carriage Association of New York said. "It caught its toe in the pavement, which is quite common."

He said the driver "acted responsibly" and unhooked the carriage from the horse and took him directly to the stable.

After an inspection by the ASPCA, the horse has been "determined to be healthy," the carriage association said in an email.

But Mary Xanthos, 42, an organizer with the group Win Animal Rights who was protesting the use of carriage horses when the incident occurred, charged that the animal was overworked.

"This is the industry's busiest time," she said. "These horses were being worked non-stop, going over and over again, ride after ride without a break."

Xanthos, who used her Flip video camera to record frames of the animal on its side in the middle of the street, said the horse was able to walk once he got up.

The ASPCA is investigating the incident and said the horse will not return to work until a veterinary exam is completed.