"She worked beautifully and is at the top of her game," O'Shea said.
"It was a good hitout, although she wasn't asked to do a great deal.
"She has had a great preparation and is fit and ready. Obviously, the next two weeks will be crucial but I think she is the right sort of horse to take to Hong Kong.
"She eats well and cops everything we throw at her. She is a tough mare and I couldn't be happier."
Sea Siren will be accompanied on today's flight from Melbourne by Alcopop, who will contest the Hong Kong International Cup (2000m).
Alcopop earned his place in the cup field with his breakthrough group one victory in the Mackinnon Stakes at the Melbourne Cup carnival.
The 8-year-old pleased trainer Jake Stephens in an exhibition gallop at Strathalbyn a week ago.
Alcopop's spring campaign also included seconds to Ocean Park in the Caulfield Stakes and Dunaden in the Caulfield Cup. Dunaden also leaves Australia today bound for Hong Kong, where he will run in the International Vase (2400m).
Craig Williams rides both Alcopop and Dunaden, while Jim Cassidy will be aboard Sea Siren.
- AAP