Marsh, who is yet to lock in a rider, said the three-year-old filly was likely to have a brief spring campaign in Sydney, a tactic used successfully with Sofia Rosa, who later returned in the autumn to win the group one Australian Oaks (2400m).
"If she runs well, she will carry on to the Flight Stakes [group one, 1600m] in two weeks' time and win, lose or draw in that she will come home," Marsh said.
"If she doesn't run up to expectations, we will head back and get our spring campaign back on track in New Zealand."
Santa Catarina is raced by prominent New Zealand owner Lib Petagna under his JML Bloodstock banner. The Wellington owner has also enjoyed success with the Marsh-trained Sofia Rosa, while the Cambridge conditioner was the initial trainer of Lucia Valentina, who later went on to win three group one races for Newcastle trainer Kris Lees.
Meanwhile, Marsh said last Saturday's Listed Wanganui Guineas (1340m) winner Bobby Dazzler had taken a few days to recover from his brave performance.
"Early stages he seemed a bit tired, but I gave him a couple of days in the paddock," Marsh said.
"Today I gave him a very light canter and he seemed very bright in himself.
"We want to get to the New Zealand 2000 Guineas. How we get there is a different story. We don't need to go to any specific race, just as long as we get him there."
Marsh said he had considered an Australian campaign with the three-year-old but believes it would be a bit much for him at this stage.
"I gave it serious consideration, but I think he will be a better horse in the autumn and he was a bit jaded after Saturday, so a VRC Derby campaign might be a bit arduous at this stage."
While Marsh will be at Randwick on Saturday, he will also have an eye on progressive stayer Felaar who will line up at Ruakaka.
"Felaar is running in the Benchmark Rating 72 mile and he is on a path to the New Zealand Cup. He is going great in his work. He did absolutely nothing first-up, but it was at Te Rapa, a track with well documented issues.
"Ruakaka is not going to be his ideal track, but we want to see him attacking the line at the mile. Then we can push on and get him over ground and work him towards the Cup."
- NZ Racing Desk