Jim Cassidy has no concerns about Sea Siren's class but a good barrier draw on Thursday will further enhance the champion jockey's confidence levels ahead of the Hong Kong International Sprint.

Cassidy leaves for Hong Kong on Thursday ahead of Sea Siren's attempt to win on the world stage at Sha Tin's showpiece meeting on Sunday.

"I think she's certainly got enough class to compete with the best sprinters around, that's the least of my worries," Cassidy said.

"You don't win three out of five Group Ones if you are not up there with the best of them."

Sea Siren has reportedly settled in well in Hong Kong, impressing trainer John O'Shea in a gallop on Tuesday.

She had a light hitout on Wednesday, stretching her legs on the all-weather track.

Cassidy said the plus for Sea Siren was the fact she had been set for the race and had not been overtaxed in the lead-up.

The mare took out the Group One Manikato Stakes (1200m) first-up at Moonee Valley before finishing second to Mental in the Group One Patinack Farm Classic at Flemington.

"This is not an afterthought and she's travelled up well, settled in good and we just need a nice barrier and a nice ride," Cassidy said.

"I expect her to run very good."

While Cassidy admitted an ideal draw wasn't crucial to Sea Siren's winning chances, he said it would play a big part.

"It's always nice if you can draw a good marble, it makes it easier," he said.

"If you draw badly it makes it harder. I've seen good sprinters in big races draw bad and get beat, where if the good chances draw well it just makes them a lot harder to beat."

Cassidy has ridden Sea Siren in her past seven starts which have netted Group One wins in the BTC Cup (1200m), Doomben 10,000 (1350m) and the Manikato.