Lydia Ko's soaring reputation received another boost on Sunday as the world number one carded a two-under-par 71 in the final round to win the LPGA Australian Open by two shots in Melbourne.

Ko - joint overnight leader at the start of play - had an eagle and two birdies to go with two bogeys as the 17-year-old New Zealander clinched the tournament for the first time with a total of nine under through 72 holes.

The six-time LPGA Tour champion, who won for the first time since claiming the top ranking last month, sealed victory with a par putt at Royal Melbourne as she became the first Kiwi golfer since Marnie McGuire in 1998 to win the LPGA event.

Ko finished two strokes clear of South Korean Amy Yang (72).

Yang had to settle for a runners-up cheque after she bogeyed two of her final four holes to fall off the pace.

Thai teenager Ariya Jutanugarn, who shared the lead with Ko before teeing off on Sunday, ended the tournament five shots back following a final-round 76 that included five bogeys.

South Korea trio Chella Choi (72), Ilhee Lee (71) and Jenny Shin (74) tied for fourth at two under.