Aiden Markram and Ryan Rickelton will continue their opening partnership, with the pair locked now in at the top of the order for the Proteas in all three formats.
Bavuma is one of five new faces that has flown to Australia following the T20I series, which the home side won 2-1, along with spinner Keshav Maharaj, Wiaan Mulder and top-order batters Matthew Breetzke and Tony de Zorzi.
The skipper also hinted that Dewald Brevis will make his international debut in the ODI format after playing a starring role in the T20Is, hitting a 41-ball century and fifty in the final two matches.
Fast bowler Kwena Maphaka, who impressed with nine wickets in the T20I series, was also added to the Proteas squad on Monday.
"It's always exciting when you see the young faces," Bavuma told reporters in Cairns. "Obviously the big talk has been on Brevis, (he's been) putting up his hand and showing what he is capable of.
"(I am) excited to see what he can also bring within the one-day stuff."
Australia captain Mitch Marsh, meanwhile, is expecting his team to continue the aggressive approach in the one-day format that they displayed in the T20Is.
The home side were in trouble with the bat in the all three matches but showed good composure to still come out on top in the series.
Marsh said: "Getting ready to spend three and a half hours in the field will be a little bit different for a few of the boys.
"But as a group and as a whole, nothing really changes. (There's a) bit of a mindset change, it's obviously different format. But the same stuff rolls on."
Glenn Maxwell struck a brilliant unbeaten 62 off 36 balls to help Australia beat South Africa by two wickets with one ball to spare in the third and final T20I in Cairns and seal the series 2-1.
Captain Aiden Markram says his move to the top of the order in the Proteas' T20I batting line-up was to accommodate "more destructive" players in the middle-order.
South African all-rounder Corbin Bosch has found himself in hot water for his innocuous gesture during the second T20I against Australia in Darwin on Tuesday.
Dewald Brevis struck the highest score by a South African player in a T20 International to help the Proteas power to a 53-run victory against Australia in Darwin and level the series at 1-1.
