Adelaide, Australia (AFP) - American Lizette Salas seized the outright lead after the third round of the Australian Open on Saturday as world No. 1 Lydia Ko fell even further behind at Royal Adelaide.

World No. 68 Salas stormed to 10-under with three birdies in her final five holes for a two-under 71 in the LPGA-sanctioned event.

She finished with five birdies and two bogeys to lead by two strokes from Australians Su Oh and Sarah Jane Smith along with Thailand's Pornanong Phatlum.

Salas played a superb back nine and grabbed the lead when she made consecutive birdies at the 14th and 15th before extending the margin when she two-putted for another birdie on the par-five 17th hole.

The American, whose parents are Mexican immigrants, has been strident in her social media criticism of US President Donald Trump's immigration policy, although she diplomatically stayed out of that debate at her post-round media conference.

"It would be such an honour and it would be my first win overseas, my first win with my dad here," Salas said.

"On 18 my hands were a little numb. I was just trying to relax and stay patient. We'll take it shot-for-shot tomorrow.

"It's been a while since I've been in this position. I'm just going to embrace it and have fun."

Ko's charge looks all but over after an even-par round in the morning groups.

The New Zealander was running out of holes as she tried to close the gap on the leaders, but she posted just two birdies against two bogeys in an uneventful round.

Ko began the day nine shots off the lead at even-par for the tournament and subsequently failed to make any ground and was in joint 35th heading into the final 18 holes.

"I think I was playing a couple of yards for the coolness and the temperature itself, but it wasn't easy," Ko said.

Ko admitted her work off her tee let her down as she tried to get back into contention.

"I didn't hit my drives very well compared to the last two days," Ko said.

"My putting stroke was good but not many putts went in. Hopefully I'm just saving it up for tomorrow.

"I've got one day to go. Hopefully it'll all come together. You just never know."

Thailand's world No. 2 Ariya Jutanugarn was six shots off the lead in a tie for 14th place after a two-under 71, her third sub-par round of the tournament.