Like humans, some horses have naturally athletic physiques, while others need a little more exercise in order to reach their ideal competition weight.

Miss Siska falls into the second category and trainer Matthew Smith admits most of his focus has been on trimming her down since the burly mare arrived on his doorstep mid-year.

"She is a big mare. She's 570 kilograms and they take a power of getting fit," Smith said.

"So we just gave her those couple of runs and got her fitness where we wanted it and then gave her a freshen up to come back and have a crack at these races."

Miss Siska will resume in the Festival Stakes (1500m) at Rosehill on Saturday, en route to a possible berth in next month's Villiers Stakes at Randwick.

She has the benefit of two early-spring runs for Smith, including a seventh to I Am Superman in the Group Two Shannon Stakes in September when she was beaten less than three lengths.

Smith believes the seven-year-old is in better shape this campaign and while she is at an age when most mares swap racing for breeding, her owners have an appetite to continue her racetrack career while she is enjoying it.

"They love racing so they're keen to keep her going if she can perform at the right level," Smith said.

"If she runs up to her best form she will be competitive for sure."

Miss Siska was a dual Group winner in Melbourne at the start of the year, taking out the Carlyon Cup before claiming the scalp of quality galloper Kings Will Dream at weight-for-age level in the Peter Young Stakes.

She has drawn ideally on Saturday in barrier three with Tim Clark to ride.

Godolphin won last year's Festival Stakes with Ranier and that horse returns to defend his title on Saturday.

He is one of three runners for James Cummings, who will also saddle up early favourite Phaistos and top weight Gaulois.

The Festival Stakes is timed to be a key lead up to the Group Two Villiers Stakes (1600m) at Randwick in two weeks, although no horse has claimed the double since Monton in 2011.