Apprentice Hollie Doyle has been placed on standby to replace Michelle Payne in the Shergar Cup at Ascot but officials are confident the Melbourne Cup-winning jockey can take part.

Payne has not been feeling well since she arrived in England and created a stir when she left a media event which went longer than she expected.

Ascot head of communications Nick Smith said he hoped she would be well enough to ride in the international jockeys team challenge on Saturday (Sunday AEST).

"Michelle is feeling a little better today, I understand, and hopefully by tomorrow she'll be fighting fit," Smith said.

"As this is a unique event it made sense to put plans in place. We didn't want to be rushing around in the morning looking for somebody to step in."

Doyle is the leading female rider in Britain this year with 35 wins and would join Hayley Turner and Emma-Jayne Wilson on the Girls Team if Payne was unavailable.

Payne's brother-in-law Kerrin McEvoy is the captain of the Rest of the World team.