Former New Zealander Sacred Falls is still to justify his lofty reputation in Australia but trainer Chris Waller is adamant he will.

Unbeaten in six starts in his homeland, the colt has finished fifth at his only two Australian runs in the Royal Sovereign Stakes and Randwick Guineas.

On Saturday he will step out in the Group One Rosehill Guineas where he takes on gun three-year-olds It's A Dundeel and Fiveandahalfstar.

It is no easy task but one thing Waller is certain of is that Australia has yet to see the best of Sacred Falls.

"He's had no luck in Australia," Waller said.

"First-up he struck a wet track which he didn't appreciate, he can't quicken on it. He's got a massive turn of foot that we've seen only in trackwork in Australia.

"Second-up he got cannoned into at the 1400-metre mark and he was four-wide from that point through no fault of our rider."

The rider that day was Corey Brown who warmed the saddle for regular partner Leith Innes.

Innes chose to remain in New Zealand where he won the Oaks but he is making the trip to Sydney this weekend.

Perhaps the biggest query over Sacred Falls' Guineas chances is whether he will run a strong 2000m.

Saturday's race will be his first test at the distance but Waller doesn't see it as an issue.

"He's won a mile Group One (race) in New Zealand which I think is a tough mile, they race with pressure on all the way," he said.

"He's had the benefit of a mile last start when he got to the line very well after being four-wide the whole way so, realistically, I don't think the 2000 metres should be a problem."

Sacred Falls is a $9 chance with TAB fixed odds which has Randwick Guineas winner It's A Dundeel a dominant $1.85 favourite.

Fiveandahalfstar ($3.60) is second pick although his trainer Anthony Cummings won't decide until race morning whether he backs-up from his second in the Ranvet Stakes last Saturday.

The gelding has finished runner-up at all four starts this campaign, the past two when taking on older horses.

If Fiveandahalfstar does run, Waller believes the tactics connections employ could hold the key to the race.

"I'll be interested to see what Fiveandahalfstar does," Waller said.

"Does he go into the race thinking I'm the fittest horse and try to outstay them? But then that might just suit It's A Dundeel.

"He's got form against the older horses and against some of these horses as a three-year-old. It will make it interesting what tactics they follow."