Sweet Idea will have to pass a veterinary examination even before she faces a test of a different kind in the Group One Myer Classic.

Trainer Gai Waterhouse reported Sweet Idea had a bruised heel which the stable had been managing.

The mare, who is equal favourite for the Myer Classic, has missed no work and will be inspected before the race.

The multiple Group Two winner worked on the course proper at Flemington on Tuesday in preparation for her bid to break through at Group One level in Saturday's 1600m feature for fillies and mares.

The consistent and tough performer has been placed in three Group Ones including a close second to Steps In Time in the Coolmore Classic (1500m) decided by a photo.

But the Coolmore distance is as far as Sweet Idea has raced and she will have to venture to uncharted territory in the Myer.

Waterhouse dismissed the 1600m as a concern.

"I think she'll run it with her eyes shut," Waterhouse said.

Rival trainer John Sargent is not as convinced and hopes his entrant Neena Rock is the horse finishing too strongly for her rivals.

"She'll get the mile. She's won over a mile in Group races so we know she'll stay," Sargent said.

"When we're talking about Sweet Idea and Catkins, there's two of the favourites there that are doubtful at the trip. But at least she will hit the line hard."

Neena Rock won a Group Three over 1600m at Trentham in March and was sent to Sargent by her owner and former trainer to chase Australian black type.

The six-year-old daughter of Fastnet Rock achieved that in the Group Three Angst Stakes (1600m) at Randwick last start.

Sargent said Neena Rock was on an upward spiral and from barrier six on Saturday should find a nice position.

Catkins was narrowly denied by her former stablemate Red Tracer in the Myer last year but trainer Chris Waller admits the mare is racing a length below her best.

"We saw what she could do last year when she was at her best and almost beat her stablemate Red Tracer but she is a length off that," Waller said.

"We have taken the blinkers off to try to get her to conserve energy."

May's Dream, winner of the Australasian Oaks over 2000m, is equal favourite at $5.50 with Sweet Idea while Neena Rock is at $7.50 and Catkins is $8.50.