Stewards have opened an inquiry into how two horses including the winner carried the wrong saddle cloths in a race at Toowoomba.

Number five saddlecloth was first across the line in a race on Saturday night, but instead of being carried by Unimaginable, it was being worn by the horse Royal Warfare.

Unimaginable was shown on the semaphore board as the winner, but after the mistake was discovered the numbers were changed to show Royal Warfare, who should have had number four, had won.

It was confirmed both horses had carried their correct weight and started from the correct barriers.

After the race both horses were also checked to be identified correctly by their brands.

Chief steward Peter Chadwick, who was not at the meeting, said he had called for a review of the situation as there were several check points to ensure it should not happen.

"I was left almost speechless when told as there are procedures in place to ensure it does not happen," he said.

It is the latest in a line of Integrity errors including the wrong horse running in a race at Rockhampton and the wrong fourth placegetter being declared in a race at Toowoomba on Weetwood Handicap day.