Franz was forced to share a first round lead with Korean Hyun Park after both drawing their scores level on 67, while Van Niekerk fell three shots off the pace.
Franz, who is hunting a second successive title after his success at Wingate Park, pushed into pole with his second round shooting with his four-under-par 68 on Tuesday.
Van Niekerk closed him down, however, as he did well to come within striking distance of Franz to trail him by two with a 67.
Van Niekerk has notched six top 10 finishes in 10 starts since February and is keen to convert two runner-up finishes to victory.
“Some days I am just delighted at the level of consistency I have achieved in the last three months, and on other days, I feel frustrated that I haven’t closed the deal,” the 23-year-old BSc Construction Management graduate said.
“I seem to let myself down with silly mistakes in the final round. I know the victory will come; I just have to keep a lid on my impatience.”
