After streeting to 17 under the card with 35 bogey-free holes across the opening two days, the 40-year-old Kiwi made a double-bogey six from the middle of the fairway on the final hole of the Creek course on Friday to sign for a seven-under 65.
It still left him atop the leaderboard at 15-under 129, two strokes clear of young Australian amateur star Declan O'Donovan.
With his partner working fulltime and two young children at home to look after, Geary has had to cut back his travelling commitments in recent times.
But he can still shoot very low on his day, as evidenced by back-to-back rounds of 64 and 65 at 13th Beach and a third-placed finish at last year's New Zealand Open.
"The way I came into the week I wasn't feeling great about the way things felt and to be honest some of the long stuff is still pretty rough," said Geary.
"But I managed to get it around and the scoring is really sharp so that's kept me in it."
It's done a lot more than keep him in it.
Even with the untimely double-bogey on the last hole, no-one got within two shots of Geary.
"It all turned to custard on one hole but to be honest it was coming because I hit a few loose ones out there and got a bit lucky," he said.
"It would have been nice to have (the bad hole) earlier on and finish on a better note because it does make lunch taste a bit off.
"But I've got the chance to work on my game for tomorrow."
The 21-year-old O'Donovan has enjoyed a decorated amateur career, becoming one of a select few to win back-to-back NSW Amateur titles.
"I don't think I'll be amateur for too much longer - maybe the next couple of years," he said after carding rounds of 65 and 66.
"Then pro golf, the PGA Tour - 100 per cent that's my goal."
Australians Austin Bautista and Lachlan Barker were tied for third at 12 under, a shot clear of Shae Wools-Cobb and New Zealander Michael Hendry, who won this title two years ago and is house-sharing this week with Geary.
First-round leader Kade McBride had a much tougher day on Friday, signing for a one-over 73 on the Beach course to slip back to equal eighth at nine under.
