Ko remains cool in Christchurch quake

World No.1 Lydia Ko was unfazed by a severe 5.7 magnitude earthquake which hit Christchurch just minutes before she teed off at the NZ Women's Open.

A severe magnitude 5.7 earthquake that hit Christchurch early on Sunday afternoon has not stopped Lydia Ko's progress towards the defence of her New Zealand Women's Open golf title.

Ko was just 10 minutes from teeing off in the final round of the event at Clearwater Resort when the quake rumbled for 10 to 15 seconds.

The clubhouse at Clearwater swayed noticeable but on the course play continued uninterrupted.

The shake didn't seem to deter Ko, who made a regulation par on her first hole to remain at her overnight score of eight-under par and on top of the leaderboard.

She's been joined there by Denmark's Emily Pedersen, who responded to the quake by making an eagle on the par-5 second hole.

There were no reports of balls moving on the green as a result of the rumble.