The top-seeded Azarenka has yet to lose a match this year and easily polished off Agnieszka Radwanska of Poland, 6-2, 6-4. The third-seeded Stosur won the first set of her semifinal against Marion Bartoli, 6-3, when the Frenchwoman was forced to retire because of a calf injury.
Azarenka improved to 16-0 in 2012 and will try for her third title in as many events. She won the season-opener in Sydney before capturing her first Grand Slam title at the Australian Open last month.
The victory in Melbourne vaulted her into the top ranking on the WTA circuit.
Radwanska, seeded fourth this week, simply needs to avoid Azarenka in the draw. She has lost to the Belarussian in each of her three events in 2012, first falling in the Sydney semifinals and then in the Australian Open quarters.
Azarenka is 10-8 all-time in finals, while Stosur is just 3-10. The Australian is coming off a banner 2011 season that included her first major championship at the U.S. Open, but the start of this year had been a complete disaster until this week.
Stosur had just one win in four matches to start 2012, including a disappointing first-round loss to Sorana Cirstea at the Australian Open. This is her first event since flaming out in her home country and she avenged that loss in Melbourne by beating Cirstea in the second round this week.
Bartoli was trying to reach her second straight final, having lost to Angelique Kerber last week in Paris, but said she injured her thigh during a quarterfinal win Friday against Lucie Safarova. After battling through the first set Saturday, she decided after a couple of points in the second set to call it quits.
Azarenka also appeared to injure her right ankle during Saturday's semifinal, but managed to finish the match and improved 8-3 lifetime against Radwanska.
Sunday's final could be a one-sided affair, as Azarenka has never lost to Stosur in five lifetime meetings. Stosur has yet to even win a set and suffered a 6-2, 6-2 drubbing at the WTA Championships last year in the most recent meeting.
The 2012 Doha champion will earn $385,000.