Tomic ousted third-seeded Andreas Seppi 7-6 (12-10), 6-4 by saving all six break points he faced.
There was little to choose between Seppi and Tomic in the first set as each won 49 points, although Seppi failed in the six break chances. Tomic cashed in his only break opportunity of the second set and that boosted him into his first ATP final.
Anderson saved a pair of match points in getting past defending Apia champion Julien Benneteau 3-6, 6-4, 7-6 (10-8). Anderson used a second-serve ace to wipe out Benneteau's first match point at 5-6 of the third set.
Benneteau saved a match point himself with consecutive points giving him a 7-6 lead in the tiebreaker but Anderson rallied again for the win.
While Tomic on Saturday is making his first finals appearance, Anderson is 2-1 in title matches. He is also 1-0 in his career against Tomic.
The Apia International championship includes a first-place check for $78,800, with the loser earning $41,540. Benneteau and Seppi each left Sydney with $22,500 for making the semifinals.