Glen Boss has dismissed the three-year-olds as Ocean Park's main Cox Plate dangers, nominating two proven older horses as the biggest obstacles to overcome.

Plenty of interest in the lead-up to the $3 million Cox Plate (2040m) on Saturday has been on the quality of the three-year-olds Pierro, All Too Hard and Proisir.

But Boss, who has won two Cox Plates, the latest in 2009 on three-year-old So You Think, declared the younger brigade weren't the horses he feared most.

"Green Moon and More Joyous are the two," Boss said.

"More Joyous will step up again. She needed that run the other day (in the Toorak Handicap).

"She had two soft wins up in Sydney, they were like barrier trials, and then she got down here and had a hard run so she probably needed that. Her and Green Moon are the horses to beat, for sure."

But Boss is confident he has the right horse in triple Group One winner Ocean Park to topple that pair.

The jockey was aboard Ocean Park for his final serious gallop at Moonee Valley on Tuesday and said the entire was his typical self in the hitout.

"He's just perfect for me, nothing has changed with him," Boss said.

"He worked basically identical to every other gallop I have given him. You just don't want to see changes in him, and he didn't change.

"He's a lazy track worker. He just goes along and does his thing so for me it's all good."

Ocean Park started his campaign at home in New Zealand with a Group One victory in the Makfi Stakes (1400m) at weight-for-age before heading to Melbourne for wins in the Group One Underwood Stakes (1800m) and Group One Caulfield Stakes (2000m).

"He's the right horse for the race," Boss said.

"He's a weight-for-age horse and he's doing everything he has to do with three pretty good wins this preparation.

"You can't fault him or knock him in any way. He can sprint off the mark, he can sustain runs, the distance is not a problem, he's got good fitness levels now, and to the eye he just looks fantastic."

Three-year-old Pierro is favourite ahead of Green Moon with Ocean Park on the third line.

Proisir and All Too Hard, both three-year-olds, are the next two most favoured runners.