Girl Guide has not yet reached the heights of her younger sibling Gregers but David Hayes says the mare is quickly making up for lost time after a delayed start to her career.

The four-year-old can kick off a potentially big day for the family with victory at Sandown on Saturday, just over an hour before her three-year-old half-sister Gregers chases a breakthrough Group One win in the Robert Sangster Stakes in Adelaide.

Their trainer is confident about the chances of both horses.

"They are both in really good order. Gregers has been set for this race for a long time and we think we've got her right," Hayes said.

"And Girl Guide is just going through her classes beautifully.

"I go in confident they are going to run very well.

"Gregers has drawn a bit awkwardly but we've got Craig (Williams) on so hopefully it will be all right."

Girl Guide did not make her debut until February because of injury while Gregers has been up and running in feature races since she was a juvenile.

"She (Girl Guide) broke her wither as a young horse which kept her back a year, and then she went shin sore twice because she didn't get tested as a young horse," Hayes said.

"Now she's catching up to her sister a bit. I think she's very talented and should nearly be undefeated after four starts."

Girl Guide won on debut at Bendigo before being narrowly beaten at Moonee Valley at her second start.

She has since added midweek city-class wins at Mornington and Sandown ahead of Saturday's benchmark race for fillies and mares over 1300m.

Another win on Saturday could earn her a shot at her first stakes victory two weeks later.

"If she wins well there's a Group Three on the 10th of May in Adelaide for mares," Hayes said.

"So that's the plan."

Gregers, meanwhile, has won at Group Two level last preparation and performed admirably in feature sprints this autumn, running fourth in both the Group One Oakleigh Plate and William Reid Stakes.