According to the bookmakers Roger Varian's Kingston Hill is the only credible rival to Australia in Saturday's Dubai Duty Free Irish Derby at the Curragh but the trainer would be "very reluctant to run" on fast ground.
Australia beat Kingston Hill by just over a length in the Investec Derby earlier this month and there are a few who believe the more conventional nature of the County Kildare track will suit the Newmarket raider more than Epsom's twists and turns.
However, despite already having made the journey over the Irish Sea, Varian has reiterated that he will not risk the Racing Post Trophy winner on ground that he thinks is too fast.
"He's gone over there today, he should be there by now I think," said Varian.
"I think the weather tonight and into tomorrow morning is key. They are forecast 8-12mm of rain and hopefully they get that and a bit more.
"I hope the ground is at least good by Saturday.
"I would be very reluctant to run him on anything described as faster than good."
Australia and Kingston Hill are two of seven declared runners.
Aidan O'Brien's choicely-bred Australia fell just short when third in a red-hot renewal of the Qipco 2000 Guineas but put the record straight at Epsom.
Australia is one of four runners for O'Brien with Geoffrey Chaucer, Kingfisher and Orchestra all taking their chances in a race the Ballydoyle handler has dominated in recent years.
O'Brien won seven successive renewals before Jim Bolger's Trading Leather snapped his sequence last year.
Dermot Weld has declared Derrinstown Derby Trial winner Fascinating Rock, who finished eighth at Epsom, but he would also like to see a little more ease in the ground.
Speaking at Naas on Wednesday evening, Weld said: "It's pretty ground dependent. Hopefully they get plenty of rain - it's pretty firm at the moment so they'll have to get the rain or water it sufficiently.
"I understand they have a difficult decision as rain is forecast so they might not want to water but I'm sure they'll get it right.
"He's in great form. He hasn't been burning up the gallops or anything since Epsom because I haven't asked him to, he's just had an easy time.
"If he runs, I'm convinced we'll see the horse who won his Group races in Ireland rather than the one that ran at Epsom."
The only other runner is John Oxx's Ponfeigh.
RaceBets make Australia 9-1 to break St Jovite's winning distance record of 12 lengths in 1992.
The firm's spokesman Joseph Burke said: "It has been one-way traffic in the Dubai Duty Free Irish Derby, with every single horse in the race drifting with the exception of Australia who has hardened to 3-10 favourite and it appears to be simply a matter of how far he wins by.
"With that in mind, the winning distance specials for Australia have also proven popular and he has shortened to 6-4 to win by three lengths or more and to 9-4 to win by five lengths or more.
"With Aidan O'Brien chasing his eighth Irish Derby winner in the past nine years and supplying four of the seven runners, we quote him at 16-1 to supply the first three home, a feat he has achieved as recently as 2010 and 2011."