The bodies of 12 horses found dumped in SA

The bodies of 12 horses, including two unraced thoroughbreds, have been found illegally dumped in a conservation park south of Adelaide.

The Environment Protection Authority and thoroughbred racing officials are investigating the discovery in the Mt Magnificent Conservation Park.

The EPA says the remains have been there for at least six months but it's unclear how and where the horses died.

Thoroughbred Racing SA says the site has been examined by stewards and a veterinarian and two of the horses have been identified as unraced thoroughbreds.

"It appears that these animals were disposed at this location over a period of time, prior to their recent discovery," EPA investigations manager Stephen Barry said.

"The more recent disposal of carcasses was two adult horses."

Thoroughbred Racing SA chief executive Jim Watters said the incident was concerning and stewards were working with authorities to identify those responsible and determine whether any rules of racing had been breached.

"Integrity and animal welfare are extremely important to us," he said.