Derby favourite Australia's position at the head of betting for the premier Classic has been strengthened over the weekend without him leaving his box.

One of the best-bred horses to see a racetrack, the Aidan O'Brien-trained Australia only finished third in the 2000 Guineas but looks guaranteed to improve for the step up to a mile and a half (2400m).

The Sir Michael Stoute-trained Snow Sky, winner of the Lingfield Derby Trial on Saturday is not a certain runner and bookmakers have been unaffected by Fascinating Rock's win in Ireland a day later.

"Teddy (Grimthorpe, racing manager to Khalid Abdullah) obviously has to speak to the Prince as he pays the bills, but I'd like to see the Dante before committing him to the Derby," Stoute said.

"I wouldn't want to jump now and say he'll definitely go to Epsom. It does encourage you, but we will sit tight."

The Derrinstown Stud Derby Trial at Leopardstown was a messy affair and was won in the stewards' room by Fascinating Rock who went off the even-money favourite for Dermot Weld and Pat Smullen.

The John Oxx-trained Ebanoran was first past the post, but interference caused to Fascinating Rock and third placed Geoffrey Chaucer prompted a stewards' inquiry, leading to the first two ultimately swapping places.

"I don't want to win any race that way," Weld said.

"I'd be pretty definite that he'll go to Epsom and he'll certainly have learned a lot."

The lack of a dominant winner of either Trial meant Australia hardened as favourite with several firms going 5-4 and Ladbrokes shortest at evens (from 6-4).