Lydia Ko has survived a challenging second round to be just four shots off the lead with two rounds to play of the Australian women's golf open in Adelaide.

Ko's mixed three birdies with a bogey to finish the day two-under, and will start the day tied for 11th at four under overall, four shots off the pace.

Ko says the course and conditions have make things tricky, particularly around the firmness of the green.

Ko begins her third round at 2:25 this afternoon.