Ko, who turns only 14 tomorrow, becomes the first golfer to have won both the New Zealand and Australian Strokeplay titles in the same year.
In both events, Ko defeated her good friend and rival Cecilia Cho although this time the margin was nine shots compared to the narrow playoff victory she recorded over Cho in Australia.
Ko took a five shot lead into today's final round and at no stage did she appear likely to be caught. The winning margin would eventually be nine but such was the pair's domination of the event that there was a massive 10 shots back to the third placed Jayvie Agojo of the Philippines.
The leading 32 qualifiers from this week's event will qualify for the New Zealand Women's Amateur Championship beginning tomorrow morning at the same venue.