The Queen's horse Carlton House is among the notable withdrawals from the Caulfield Cup but Irish St Leger winner Royal Diamond is still in the mix.

To contest the Caulfield Cup, Royal Diamond would have to miss his defence of the Irish St Leger this weekend and instead enter quarantine.

Racing Victoria's international recruitment officer Leigh Jordon said the payment of the first acceptance for Royal Diamond had come as a pleasant surprise.

"Johnny Murtagh, the trainer and rider of Royal Diamond, has advised me that he is now considering a trip to Australia for the Caulfield and Melbourne Cups rather than defending his Irish St Leger crown this weekend," Jordon said.

"The quarantine requirements mean he would be unable to do both so he will review the acceptances and advise me within the next 48 hours of his decision.

"Certainly it would be a coup for Caulfield if the Irish St Leger winner chose to compete in their race."

Carlton House, who is trained by Gai Waterhouse, remains in the mix for the Cox Plate on October 26.

Atlantic Jewel is the $3 Cox Plate favourite with Puissance De Lune second elect at $5.50.

Ninety-eight horses remain in contention for the Caulfield Cup, where Hawkspur, a Queensland Derby winner trained by Chris Waller, and the Mark Kavanagh-trained Australian Cup winner Super Cool, share equal favouritism at $9.

In the Cox Plate, there were no surprise omissions with 90 horses in the first acceptances.

Gai Waterhouse has added Tres Blue to her list of potential starters for the $6.2 million Melbourne Cup as a late entry.

The three-year-old won the Group Two Prix Deauville (2500m) in France at his most recent start and takes to 12 the number of horses Waterhouse has entered for the Melbourne Cup.