Hannah Green has ensured back-to-back titles for Australia at the BMW Ladies Championship in South Korea, emulating the feats of Minjee Lee from last year.

A birdie on the testing 17th took Green into the lead at 19-under and she was able to see her way safely home at Seowon Valley Country Club to clinch her third LPGA title of the year.

She became the first Australian woman since golf great Karrie Webb in 2006 to win three LPGA tournaments in a year, and joined world number one Nelly Korda and number three Lydia Ko among players to achieve the feat this year.

"I knew I needed to make birdies somewhere but I didn't think it would be on 17, because that was a pretty difficult pin position," the world number eight said.

"I was hoping for a bit easier two-putt on the last, but grateful that that second putt went in."

Green held off fast-finishing French golfer Celine Boutier, who had the round of the day with a 66, including a 31 on the back nine, to finish one stroke back.

After streaking ahead with match eight-unders in the first two rounds, the Australian Olympian took a two-shot lead into the final round on Sunday but was joined at the top of the leaderboard at 18 under by Thailand's Chanettee Wannasaen, who reeled off an eagle and four birdies on the front nine.

Green was one-under through her opening nine holes, but her game almost came unstuck at the 11th when her tee shot went wildly left into the rough.

The 2019 Women's PGA Championship winner hit a provisional shot but was able to find her ball at the base of a tree and hacked it out, managing to only drop one stroke.

The 27-year-old West Australian could not buy a birdie until the par-four 17th when she skipped ahead of Boutier, while Wannasaen dropped a shot on the same hole to finish at 17-under.

Green held her nerve on the par-four 18th, making par to seal the win before she was joined by competitors, including 57th-placed compatriot Grace Kim, who sprayed her with champagne.

It was Green's second LPGA tour wire-to-wire victory and brought her career title haul to six.

"My putter can be hot and cold just like any other player, and certainly this week it was really hot, so I was just trying to take advantage when things are going well," she said.

"Obviously, it's difficult to win tournaments, but I think having experienced it and having confidence on the right side of things, it makes it easier.

"But don't get me wrong, I was still really nervous playing those last three holes."

Defending champion Lee had a day to forget, following her third-round 66 with a 77 that included five bogeys on the back nine, to finish tied for 33rd.

Fellow Australian Gabriela Ruffels carded a final-round 74 to finish joint 46th.

The field in the $US2.2 million ($3.3 million) event was loaded with eight of the LPGA Tour's top 10 players and included 17 of the 18 winners this season.

The LPGA Tour moves on to the Maybank Championship in Kuala Lumpur, Malaysia this week, with Boutier the defending champion.

AAP