New Zealander Lydia Ko remains in contention ahead of the final day of the LPGA event in Malaysia after a one-under 70 that has her in a tie for third.

Her score put her 10-under after 54 holes of the $US2 million ($NZ2.5 million) Sime Darby tournament in Kuala Lumpur, four shots behind leader Pornanong Phatlum of Thailand.

Phatlum fired a six-under 65 to hold a three-stroke advantage over second-placed Japanese Ayako Uehara.

Ko picked up two birdies on her outward nine, but then double-bogeyed the par-five 12th before finishing with a birdie on the 18th.

The 17-year-old world No.3 already has two victories in her debut season as a professional.

She will take over as world No.1 from Stacy Lewis if she wins on Sunday and the American finishes outside the top 12.

Lewis carded a one-over 72 to be five-under and in a share of 20th.