Koh, who started the day on 17-under-day, forged ahead to finish an incredible 22-under-par after three rounds at Millbrook.
If he can continue that form on the final day tomorrow, he will be hard to reel in.
Australian Ryan Peake moved up the ladder and moved into second spot, finishing at 18-under-par.
Japanese golfer Kazuki Higa, South African Ian Snyman and China’s Bobby Bai are all still in the hunt finishing at 17-under-par.
Australian Elvis Smylie also came home strong at 16-under-par.
Sam Jones, who started the day on 5-under-par, moved himself well up the table, finishing with a score of 61 yesterday to go 15-under-par.
Australian James Marchesani, who started the day on 14-under-par, also finished 15-under-par.
Jones led the Kiwi contingent with Mark Brown and Daniel Hillier – who is supported by caddy Steve Williams – who are 12-under-par.
Queenstown favourite Ben Campbell, former champion Michael Hendry and Josh Geary finished on 10-under-par.
The New Zealand Open, with a purse of $2 million, will crown its 104th champion tomorrow.
The winner will be awarded a qualifying spot at the British Open, with the Claret Jug on display at Millbrook this week.
