The 49-year-old Zimbabwean stands at 14-under par 202 and is in front of Darren Fichardt, who finished the day in second place at 11-under-par 205. Fichardt, the first and second round leader, carded a 2-under 70.
I didnt plan on leading the tournament, said McNulty. My aim was just to play solid golf and, as it turned out, I hit a lot of quality shots out there.
If McNulty is able to hang on for victory he would be the oldest player to win a tournament on the Sunshine Tour since 1952, when 52-year-old Sid Brews won the South African Open.
Theres still a long way to go. I cant get ahead of myself. Im happy with my performance, but Ill wait for the back nine on Sunday.
Alan McLean (68) and Craig Lile (70) are both five shots back of the leader at 9-under-par 207.
McNulty last won on the Sunshine Tour in 2001 when he captured both the Nashua Masters and the South African Open.
Full-field scores from the MasterCard Masters