Hannah Green has joined fellow Australian Steph Kyriacou in the mix with a fine five-under-par 67 in the second round of the LPGA Tour's Women's World Championship in Singapore.

Green rebounded from an opening 74 to soar from 36th into a six-way tie for ninth at three under, four shots behind French halfway leader Celine Boutier at Sentosa Golf Club.

The former major winner carded six birdies to offset her lone bogey on the par-4 ninth hole at the Tanjong Course on Friday.

Boutier sizzled with the low round of the day, a bogey-free eight-under 64 to take a major stride towards capturing women's golf's top ranking for the first time.

Currently world No.3, Boutier must win and have the top-ranked Lilia Vu finish 26th or worse at the 66-player, no-cut event to usurp the American.

If such a scenario transpires, the 29-year-old would become the 19th individual player - but first Frenchwoman - to claim the top ranking.

Vu shares 21st at one under after slumping to a 74, having started the day in second place.

Japan's Ayaka Furue is Boutier's closest pursuer, one shot behind at six under after matching Green's 67.

Swede Madelene Sagstrom (68) is third at five under.

Kyriacou remains the leading Australian in a five-way tie for fourth at four under, after a 69 to follow her opening 71.

First-round leader Sarah Schmelzel (72) of the USA, Koreans Peiyun Chien (68) and Hyo Joo Kim (70), Japan's Nasa Hataoka (69) and American first-round leader Sarah Schmelzel (71) are also three strokes adrift of Boutier.

Playing her first event of the year, and first since tweaking her swing following her multi-million-dollar switch from Srixon to Callaway clubs, Australia's world No.5 Minjee Lee shot 71 on Friday to edge back to one over.

Compatriot Grace Kim is also one over, sharing 33rd spot, after matching Lee's 74-71 start to the $US1.8 million tournament, the second of three successive events in Asia.