Bayrir has earned a reputation as a genuine international racehorse but trainer Chris Waller insists there will be much guesswork surrounding the import's Australian debut.

As a member of leading French trainer Alain de Royer-Dupre's team, Bayrir was given his chance at the highest level in Group One races in three countries last year.

But even though there has been strong pre-post support for Bayrir at Rosehill on Saturday, Waller is keeping first-up expectations in check.

Perhaps the only horse racing at the meeting considered to have genuine spring Group One claims, Bayrir will make his Australian debut in the $100,000 Listed Winter Challenge (1500m).

Bayrir's CV is impressive as a United States Grade One winner, a runner in last year's Prix de l'Arc de Triomphe and a midfield finisher in the Hong Kong Vase.

Yet Waller says there is still much to learn about a horse which hasn't raced at a distance below 1800m in an eight-start career which has delivered four wins.

"I'm sure he will get to the level we want him to but whether that is in the spring or the autumn I don't know," Waller said.

"He's been with us for a while and we have given him plenty of time but he might be one of those horses who might be a next-preparation horse.

"Against that he did a good job as a three-year-old around the world which is always a good test. He wasn't sheltered in his own backyard."

Waller likens Bayrir in type to the progeny left by the breed-shaping dual hemisphere sire Danehill.

It's an observation which promises to be good news for punters who have already backed the five-year-old from $6.50 to $4.80 in early Winter Challenge wagering.

"He's a tidy, compact horse," Waller said.

"I'd say he's a Danehill-type which is quite good because it will help him in the shorter distances. It should give him a bit of speed."

Bayrir, a Hugh Bowman mount, has been given two barrier trials and was kept under restraint each time.

"They have been soft trials and it is hard to get a good read on him because he hasn't been let go yet," Waller said.

Waller will also run Coup Ay Tee ($6) and Wazn ($12) in the Winter Challenge for which Under The Sun is the $3.20 favourite.