The Springboks were routed 49-0 by the Wallabies on July 15 in their opening match of this year's Tri-Nations tournament, but did show a slight improvement in last weekend's 35-17 defeat at the hands of New Zealand.
Du Preez replaced Enrico Januarie for the All Blacks match and impressed to such an extent that he will be handed the number nine shirt against Australia next Saturday.
Coetzee reckons Du Preez's ability with the boot will be a valuable weapon in Sydney.
"We certainly can use Fourie to greater effect in the role of tactical kicker," Coetzee told Beeld.
"Against a team such as the Wallabies, who like to play to a certain structure, it is particularly important to force their back triangle to turn.
"Our line-outs are so good that we can afford to kick the ball into touch.
"In a way you give away possession, but our opponents know what a player such as (lock) Victor Matfield is capable of. Therefore, they are always under pressure at line-outs."
Coetzee believes Butch James, another solid kicker, deserves to remain at fly-half.
"I agree with (Springbok coach) Jake White that we should now, in the interest of continuity and consistency, start sticking to one half-back combination," Coetzee said.
"What I saw of Butch made me feel he and Fourie could become a winning combination. Both have the ability to dictate matches with the boot."