Midway through her round Ko was five shots behind the clubhouse frontrunners but she rallied with birdies at both the par fives on her second nine as she settled into a better rhythm.
Ko signed for a two under par 70 and hoped she would gain momentum if her putting improved.
A significant crowd of 5812 watched the action with the bulk of them following Ko and lining every vantage point from tee to green to get a consistent view of the teenage star.
Ko striped her opening drive on the 10th hole in her bid to claim a second national title and while she had the length to reach the par 5 she pushed her shot into a greenside trap. Her game was a bit like that on the opening nine where she balanced one birdie with a bogey on the 15th after tugging her drive and taking a penalty drop.
She turned in par and at that stage was five shots behind Denmark's Nanna Koerstz Madsen who had a bogey free round and the USA's Samantha Troyanovich who picked up six birdies around one bogey on the fine putting surfaces.
Hannah Green, an Australian amateur and American pro Beth Allen led early before being caught as the winds kept gusting in from the nor-east while Anne-Lise Caudel from France and Arianne Skarpnord from Norway finished strongly finished strongly.
By Wynne Gray of the New Zealand Herald
