The world number one had little trouble securing a four shot victory over Hannah Green in the final round. She hit a one-under 71, with two bogeys and five birdies to take her second victory in three years at the tournament. On Saturday she broke the course record with her
Australian amateur Green one stroke clear in second, with Denmark's Nanna Koertsz Madsen of Denmark in third and Marianne Skapnord and Beth Allen tied for fourth.
Following her win Ko said: "I really wanted to win in front of such great crowds, this is probably the biggest crowd I've seen." said Ko, who admitted she enjoyed her walk up the 18th.
"I hit a really good shot in, if I was chipping I would've been more nervous, but when you hit a good shot on the green it's a nice feeling.
"It's always cool winning on home ground. We were walking up 16 and (playing partner Giulia Sergas) said 'they like you'. I said 'well, it's home'. It's just great, the spectators have been amazing. It's one of the best tournaments I play each year, the atmosphere and everything."
Ko had chosen to skip the LPGA Thailand Open, which had a much bigger purse, to compete at the New Zealand Open, and she was rewarded by a massive crowd cheering her on.