It has taken a long time to entice Irish trainer Aidan O'Brien to have another crack at the Melbourne Cup after his trio of runners ended up well beaten in 2008.

He now has four possibilities for the $6.2 million race, including Saturday's Irish St Leger winner Order Of St George.

Racing Victoria international recruitment officer Leigh Jordon admits it's been a hard job courting O'Brien back for another go after 2008, when the Irishman's three jockeys were all questioned about their riding instructions after straggling home at the rear having earlier led the field.

"I'm hoping that this year's the year that he comes back," Jordon said.

Jordon said the O'Brien stable was preparing for quarantine but wanted to assess Tuesday's weights set by Racing Victoria handicapper Greg Carpenter.

Carpenter is more bullish and believes O'Brien will have multiple Melbourne Cup runners rather than one.

"I think he'll have at least two runners in the race, one of them might be the older horse Kingfisher."

Aside from Ascot Gold Cup runner-up Kingfisher (53kg), O'Brien's three other possibilities - Order Of St George, Bondi Beach (52.5kg) and Fields Of Athenry (51kg) - would be the youngest horses in the race on November 3.

Jordon rates the quality of the international field as it stands as second to none, with a lot of fresh new horses joining well-knowns like 10-year-olds Red Cadeaux and Precedence who are both pursuing their fifth Cup start.

He said all the major Group One winners in Europe are in the running - despite facing tough quarantine conditions, a 30-hour-plus flight and $150,000 cost to connections - as well as Japan's current favourite Fame Game and second entrant Hokko Brave.

"You throw that in with the top-quality locals, I think this could probably be one of the best Melbourne Cups we've seen for a couple of years."

Snow Sky is on course to be the first Melbourne Cup runner for Saudi prince and Juddmonte Farms owner Khalid Abdullah, best known for racing champion Frankel.

It would also mark trainer Sir Michael Stoute's first trip to Melbourne since Distinction ran in the 2005 Melbourne Cup.

"I know over the years he's always had the Melbourne Cup in his mind. He's always just searched for the right horse, so that's got to be a good guide in itself," Jordon said.

Snow Sky is already in pre-export quarantine in Newmarket and will arrive in Australia on September 26.