Craig Parry, winner of the 2002 NEC Invitational, was one back, along with Jarrod Moseley, Gary Evans and Richard Lee in a tie for fifth with 21 points.
'It felt like the golf course was there to be had this morning,' said Parry. 'It's in great condition, the only thing is the flag places were a little bit easy today.'
O'Hern was seven points off the pace of Peter Fowler to start the day at New South Wales Golf Club and picked up four points after three birdies and two bogeys on the front nine.
The 31-year-old climbed into a tie for first, thanks to his fine play on the inward half. O'Hern tallied four birdies for eight points on the back nine.
Jones had three bogeys during his round but managed 14 points after an eagle and six birdies.
Green, who had a disappointing season in the United States in 2002, had seven birdies and one bogey for 13 points, while Price joined the crowd with seven birdies and two bogeys for a 12-point total.
'Last year was probably the toughest year of my life golfwise. I think I've made more cuts this year than I made all last year,' said Green. 'I certainly bottomed out last year. I was just beating my head against a brick wall.'
Sweden's Robert Karlsson finished alone in ninth with 20 points. He was followed by Peter Senior, Soren Hansen, David Carter, David Drysdale, Mahal Pearce, Paul Marantz and Fowler with 19 points.
Stuart Appleby came close to grabbing the lead by himself but stumbled down the stretch. He lost four points on the final two holes as the winds picked up. Appleby was joined by Paul Casey and Matthew Ecob with 18 points.
The 36-hole cut line was 11 points with 73 players qualifying for the weekend. Among those who didn't make the grade were Thomas Bjorn, Adam Scott and Niclas Fasth.
This tournament is using the modified Stableford scoring system for the second straight year. The scoring awards eight points for a double-eagle, five points for an eagle, two for a birdie and none for a par. One point is deducted for a bogey and three points are taken away for a double-bogey or worse.
This event is co-sanctioned by the European and Australasian Tours.