A winning double at Caulfield for Michael Walker has been soured by a careless riding suspension which will rule him out of the Cox Plate meeting.

Walker was banned for nine meetings for shifting in aboard Arctic Song in the straight during the final race on Wednesday, resulting in Michelle Payne's mount By The Grace shifting across the horse ridden by Glen Boss (King's Dance) and forcing him to check at the 50m mark.

Walker pleaded guilty and his ban is due to start after Saturday's Caulfield Cup meeting.

He is free to resume on October 27.

It was Walker's first suspension since November last year.

Stewards also questioned the rider about his actions in the final strides of the race, with Arctic Song narrowly beaten by London Stripe.

Stewards were satisfied Walker rode the horse out to the line by trying to push its head down with his left hand, but said the movement of dropping his right hand had given a "false impression" he might have stopped riding.

Walker won the opening race aboard Rawnaq and took out the Group Three Ladies Day Vase on Star Fashion, with both wins coming for the David Hayes and Tom Dabernig stable.