Play in the second round was completed early Saturday due to a thunderstorm late Friday which forced an abandonment at the Els Club course at the Copperleaf Golf Estate.
Coetzee, who turns 32 on Monday and is still seeking his first professional tournament victory after a prolific amateur career, had moved to the clubhouse lead on 12-under par 132 before the stoppage with a second-day score of 65.
Chile's Mark Tullo (66) and South African Tawie Der Walt (65) are in second place at 11-under par. Former US Amateur champion, Peter Uihlein (66) headed into the third round at 10 under as he also looks for a first pro career success.
The England trio of Richard Finch (66), Danny Willett (68) and David Howell (69) were among a group of 10 players tied in fifth place at 8 under and just four shots behind Coeztee in the dual European and Sunshine Tour event.
Jose Maria Olazabal of Spain returned to the course in the morning to birdie his last hole in a round of 66 to make the cut at 2 under. Joining last year's victorious European Ryder Cup captain at 2 under was former British Open winner Darren Clarke (73).