Michelle Payne has created a stir in England by reportedly leaving a Shergar Cup media function after being kept twice as long as expected despite telling organisers she was unwell.

Payne and her brother-in-law Kerrin McEvoy are both scheduled to ride in the international jockeys' team challenge at Ascot on Saturday (Sunday AEST).

McEvoy pulled out of the media event citing illness but Payne said she went on the understanding it would take two hours which stretched to four.

"They wouldn't let me leave,'' Payne told NewsCorp.

"I was up all night sick and told the lady when we left for the press conference."

Payne said she was told after four hours she still could not leave as there were more interviews to be held.

She said if she did not improve she may not be able to ride at the meeting.

"If I don't improve I probably won't have a choice anyway. Worst part is Kerrin's sick too," she said.

McEvoy won the 2016 Melbourne Cup a year after Payne became the first woman to claim Australia's most famous race.

She was scheduled to ride in the Shergar Cup last year but had not recovered from serious injuries suffered in a race fall a few months earlier.