Two South Australian trainers have been disqualified after being found guilty of attempted race day treatment of two horses and conduct intended to corrupt the outcome of a race.

Morphettville training partners Niki O'Shea and Ashton Downing have been disqualified for five years and two years respectively at the conclusion of an inquiry.

Surveillance by Thoroughbred Racing SA stewards discovered an attempt to treat Social Set and Allez Tiara en route to the Strathalbyn race meeting on May 2 resulting in the two horses being scratched from their respective races.

Stewards laid eight charges against O'Shea and six against Downing and under the most serious, which deals with conduct intended to corrupt the outcome of a race, O'Shea was disqualified for five years and Downing for two years for being a party to the offence.

The remaining charges resulted in disqualifications of between three and 18 months with the penalties to be concurrent.

The penalties come into effect on July 26, although they cannot start a horse from the time of the decision until the conclusion of their disqualifications.

The pair has Dexelation down to run at Morphettville on Saturday and Don't Doubt It at Port Augusta on Sunday.

TRSA chief executive Jim Watters said maintaining the highest possible levels of integrity and horse welfare were the cornerstone of the racing industry.

"While the penalties are severe, these were premeditated actions to try and illegally affect the outcome of a race, and in ensuring a level playing field for all of our participants, and in endeavouring to maintain the expected levels of animal welfare, the penalties must be substantial," Watters said in a statement.