Park is 16 under for the tournament after two birdies and a bogey in six holes on Sunday at Royal Adelaide.
The seven-time major winner, eyeing a 20th LPGA title, is five strokes clear of 19-year-old compatriot Ayean Cho.
Swede Madelene Sagstrom has banked two birdies in her initial five holes to move to 11 under to share third place with American Amy Olson, who is three-under through eight holes on Sunday.
Perth's Green started her final round at seven under but has dropped two shots on her front nine to be five under.
Fellow West Australian Minjee Lee, the World No.8, carded a one-over 73 to round off her week at four under.
Robyn Choi was next best of the Aussies after a 72 left her at three under while Katherine Kirk (74) ended at three over and Karis Davidson endured a torrid five-over final round to finish at 11 over.
- Steve Larkin, Australian Associated Press