The 21-year-old West Australian had established a two stroke lead after 14 holes but dropped shots at the 16th and 17th, before recovering with a birdie at the last.
“I hit the ball awesome; probably the best I’ve hit it in a long time, but I putted very poorly,” said Smith, who has won two events already in 2010, but none on the Ladies European Tour.
“I guess I can be happy with the way I’m hitting it but I’m not putting very well so I’m going to go and hit a few putts now ahead of tomorrow.
“I told myself it would be nice to be in contention going into Sunday and that’s what I’m doing. I’ve been there before and I’ve won before so we’ll see what happens.
“I felt a bit relaxed because the weather turned around quite nicely for us this afternoon. There was no wind whatsoever so you could stick it at pins. That didn’t hurt me at all.”
Scotland’s Vikki Laing (70) and South African Lee-Anne Pace (67) finished a stroke back in a share of third place at eight under par.
Earlier in the day, Laing had hit her drive on the 16th hole when play was suspended at 12:08. Play resumed briefly at 2:00 before another weather delay minutes later.