Ormsby was joined atop the leaderboard by Nick Dougherty, who shot a 5-under 66 in round two. They stand at 7-under-par 135 after two rounds.
New Zealand native and 2005 U.S. Open champion Michael Campbell climbed into contention with a 6-under 65 in round two. That moved him to minus-6. First-round leader Scott Strange is one stroke further back at 5-under-par 137 after a 1-under 70 on Friday.
Ormsby got his round going with a birdie on the first. He dropped in back-to-back birdies from the fourth to move to 2 under. However, Ormsby dropped a shot at the sixth.
The 26-year-old reclaimed that lost stroke with a birdie on the seventh. Ormsby caught fire on the second nine. He started with a birdie on the 10th and followed with birdies on 11 and 12 to move to minus-5.
Ormsby got within one of Dougherty with a birdie on the 16th at Gulf Harbour Country Club. Ormsby poured in a 20-footer for birdie on 18 to grab a share of the lead.
'I was just plodding along and making putts all day, so it was nice,' said Ormsby, who carded 12 threes in his round. 'I didn't drive it that great today, but the fairways are pretty generous. I still gave myself enough opportunities to go at some pins. I made a lot of putts, that was the best part of the day.'
Dougherty started on the back nine and had one brilliant stretch of golf that moved him to the top of the leaderboard. He opened with seven consecutive pars.
The Englishman ran off four straight birdies around the turn starting at the 17th. Dougherty birdied the fourth to get to 7 under before closing with five pars in a row.
'I played really, really well for my front nine. I stumbled a little bit at the end and didn't hit great shots the last four or five holes,' Dougherty admitted. 'Overall, I am pleased and no bogeys is always a good round.'
Campbell rolled in an eight-footer for eagle on the second and came back with a birdie on the third to get his round going. He climbed to 4 under with birdies on seven and 10.
The New Zealander moved into a share of the lead thanks to birdies on 16 and 17. On the 17th, he nearly carded an eagle as his chip shot rattled the pin, but came to rest within inches of the cup.
Campbell tapped in for birdie and a share of the lead. However, he came up short of the 18th green after a poor tee shot and could not save par from there to finish one back.
Six Australians -- David Bransdon (68), Greg Chalmers (70), Marcus Fraser (69), Nathan Green (67), Jarrod Moseley (70) and Peter Senior (69) -- are among nine players tied for fifth place at 4-under-par 138.
They were joined there by Andrew Raitt (67), Shaun P. Webster (68) and Peter Lawrie (66). Daniel Vancsik, James Heath, Michael Long and Denny Lucas are one stroke further back at minus-3.
The cut line fell at 2-over-par 144 with 67 players moving on to the final two rounds.