World No.1 Lydia Ko has smashed the course record in her second round of the New Zealand Women’s Open at Clearwater Golf Club in Christchurch.

In front of a large crowd, the 17-year-old produced a round of 61, which made her 11-under for the day and 13-under for the tournament.

She’s three shots clear of England’s Charley Hull, though the round is still being played on Saturday.

She started with a bogey thanks to a three-putt on the first hole but followed with an eagle on the second and later ten birdies.

On the front nine she had four consecutive birdies and turned in 30. She started the back nine with another four consecutive birdies and nailed another one on the 18th.

Ko chose to contest the $NZ300,000 ($A289,000) tournament out of loyalty, spurning the chance to contest a far richer LPGA event in Thailand.

She is coming off victory in the Women’s Australian Open at Melbourne last week and is seeking her second New Zealand title, having finished runner-up last year.

The three-round tournament ends on Sunday.

The previous course record was held by Mi Hyang Lee, who shot 63 to beat Ko by one shot at last year’s New Zealand Open.