Hannah Green credits a much-needed mental recharge and the home comforts of Perth for vaulting her into contention at the halfway point of the BMW Ladies Championship in Korea.

Green upstaged LPGA Tour player-of-the-year favourite and fellow WA star Minjee Lee to be the leading Australian entering the weekend after a second-round five-under-par 66 featuring five birdies and an eagle on the par-5 15th hole.

At seven under, Green is outright seventh and five shots behind American leader Andrea Lee.

The 25-year-old said a month-long hiatus had worked wonders for her energy levels nearing the end of a sapping season.

"I felt like I played good yesterday but, after having four weeks off, I was a little bit rusty," Green said.

"Today I had more bogeys on the scorecard. Just holed two really good putts, which had been a while since I've done that back-to-back."

The 2019 major winner had planned on returning to the tour at the LPGA MEDIHEAL Championship but, still feeling drained, pulled the pin.

"I only had 10 days at home and I decided to withdraw because I felt like that wasn't enough," Green said.

"I decided to take two weeks completely away from the golf course and then two weeks to get ready for this event so, yeah, mentally and physically feeling refreshed."

Steph Kyriacou is the next best Australian in a tie for 11th after moving from three under to five under with a second-round 70.

Su Oh shares 30th spot at two under following rounds of 72 and 70.

Lee, the player-of-the-year points leader, is one stroke further back in a tie for 36th after a disappointing one-over-par second-round 73.

Unrelated namesake leader Lee enjoys a two-shot advantage over fellow American Lilia Vu (66), Korean amateur Minsol Kim (70) and Thai teenager Atthaya Thitikul (71).

Like Aussie Minjee Lee, Thitikul could potentially replace defending champion Jin Young Ko at the top of the world rankings if she wins on Sunday.