Highly rated import Sea Moon has been denied his first Australian victory in the Listed Bart Cummings at Flemington after a protest from Araldo's jockey Glen Boss.

Sea Moon had a nose margin over Araldo in a three-way finish to the 2520m contest on Saturday but Boss lodged an objection, alleging interference in the final 100m.

The Mike Moroney-trained Araldo was sandwiched between Sea Moon on the outside and third-placed Gotta Take Care and Boss said Araldo had his running impeded by Sea Moon who "laid all over" him.

Stewards changed the placings after considering the "slender margin".

They said Araldo got away from Sea Moon on his own account inside the 100m mark but that Araldo had become unbalanced between Sea Moon and Gotta Take Care close to the line because of Sea Moon shifting in.

"Where it gets interesting is five strides from the line and the stewards view is that (Araldo) gets off balance as a result of Sea Moon getting in," chief steward Terry Bailey said when upholding the objection.

Brett Prebble, rider of Sea Moon, felt his mount "always had Glen's horse covered" and that his horse had affected his own chances by wanting to get in.

Sea Moon, who started $4.40 favourite, would have passed the Caulfield Cup ballot clause with victory but remains 59th in the order of entry.

Araldo is 74th in the Melbourne Cup order of entry on 50kg and is eligible for a weight penalty.

Trainer Mike Moroney is hoping for a re-handicap as the Melbourne Cup has been the aim for the German import who notched his first Australian win.

"First thoughts are we'll probably end up in the Geelong Cup and then as a last-ditched effort we might end up in the Lexus Stakes," Moroney said.

"I thought the run was terrific. He was posted three-wide most of the trip.

Moroney rated the protest a "50-50" call.

"The margin was in our favour I thought," he said.

"If it had been a long head they probably would have left it. But it was a nose margin and I think there's enough proof to say it cost us that."