Redkirk Warrior will be the sole Australian representative at Royal Ascot with two-year-old Luck Favours ruled out because of illness.
The Rosemont Stud-owned Luck Favours was scheduled to leave with Redkirk Warrior on Wednesday but spiked a temperature overnight.
Rosemont principal Anthony Mithen said the filly showed signs on Tuesday all was not well.
"She was blood-tested and showed there may be signs of an underlying infection yesterday," Mithen told Sky Sports Radio.
"She left most of her feed overnight and had spiked a temperature this morning.
"We've run out of time to get to Ascot but at least we will have a healthy horse."
The two-year-old is by Starspangledbanner who won Group One races in Australia for Leon Corstens and the northern hemisphere for Aidan O'Brien.
Bred to northern hemisphere time, Luck Favours had been scheduled to run in the Group Two Queen Mary Stakes on June 20.
The Lindsay Park-trained Redkirk Warrior will run in either the King's Stand Stakes on June 19 or the Diamond Jubilee Stakes four days later depending on the weather.
- Smaller Small Medium Big Bigger
- Default Helvetica Segoe Georgia Times
- Reading Mode