Irish trainer Joseph O'Brien has made a seamless transition from champion jockey to trainer and saddles his first Melbourne Cup runners at Flemington.

The son of champion trainer Aidan O'Brien, Joseph, 24, saddles Rekindling and US Army Ranger for Lloyd and Nick Williams in Tuesday's race in an attempt to beat his father to Melbourne Cup glory.

O'Brien senior will be represented by Johannes Vermeer on Tuesday and the closest he's come to claiming the Cup was in 2007 with three-year-old Mahler, third in 2007.

He returned the following year to see Septimus, Alessandro Volta and Honolulu finish down the track and didn't have another runner until Bondi Beach and Kingfisher contested the Cup in 2015.

After attending the Breeders' Cup meeting, Joseph O'Brien flew in from Los Angeles on Monday for his first official involvement in the race although he was in Melbourne two years ago watching his father's runners.

"It's good to be back here and I'm looking forward to it," O'Brien said.

"To be here is a privilege so to win the race would be unbelievable.

"I've got two nice horses that I hope to get a good trip around and that's all we can ask for."

O'Brien trains from Owning Hill in County Kilkenny, the property where his grandfather, his mother Anne-Marie and his father all trained before Aidan moved to Ballydoyle, about an hour away.

But Joseph says his father is only a phone call away, always handy for a young trainer starting out on a new crusade.

He prepares a team of 50 or 60 flat horses and has the same number of National Hunt horses in his care.

US Army Ranger, a $61 chance, is having his first start for the young trainer after starting his career with Aidan and running second in the 2016 Epsom Derby.

Like Mahler, Rekindling ($14) is a three-year-old in northern hemispere time and O'Brien says he has endured a busy year.

"I know his form hasn't tailed off but he's had a busy year so that's a little bit of a worry," O'Brien said.

"He's got a good draw, a good jockey in Corey Brown and I'm looking forward to it."