Rebel Rover has been a handful on the racetrack, but he could easily have a career as an Olympic distance swimmer.

The Brad Smith-trained galloper got away from handlers at Sandgate Beach, near Deagon racecourse, and rather than head to shore, took off for New Zealand.

Frantic stable staff raced to the Volunteer Marine Rescue Brisbane station and a boat took off after Rebel Rover who wasn't far from Moreton Island before they reached him.

The Sandgate Beach to Moreton island swim was often used by famous marathon swimmers Des Renford and Linda McGill during the 1970s and 1980s but these days is considered a risk because of sharks.

Smith said it wasn't possible to say how far Rebel Rover had swum but it could have been in the order of 10km to 15km .

"A couple of people took photographs of him at sea and you can clearly see Moreton Island in the background so it is a good few kilometres," Smith said.

Rebel Rover was roped and then swum back to shore - a mighty feat of endurance in anyone's book.

"Naturally, we got the vet to him and he didn't believe us when we told him. The horse's heart rate was fine and there was nothing wrong with him," Smith said.

"He is a bit sore this morning but one thing, we won't need to work him for a while.

"It brings a whole new meaning to the term water walker. One thing, he won't be going back to the beach."

Rebel Rover won three races in Victoria but has been barred a few times because of his manners.

"He has only been with us a few days and he can be a bit hard to handle," Smith added.

Smith hopes things go better for his horse Sharpe Hussler who is favourite at Doomben on Saturday.