Jeremy Jin lost to Belgium's Zizou Bergs 7-6 (7-3) 6-1, James McCabe was beaten by Frenchman Alexander Muller 7-6 (7-2) 6-7 (4-7) 7-3 and Derek Pham was knocked out by German Peter Gojowczyk 6-2 6-2.
All three were chosen ahead of Tomic for wildcards.
Tomic, the one-time world No.17, is missing the Australian Open for the first time in 16 years.
"It's our performance team that look at the decision of wildcards," Tiley told reporters on Monday when asked about Tomic.
"What it goes into is the player coming in, or the strength of their play, how they've been playing, what events they've been playing, how much they've been playing. Are they the younger part of our future generation, the younger players?
"There's many factors that go into it and it's not a quick decision they go through.
"One thing that's great, we've got a new problem, and we've got a lot more Australian players than we've had before to choose from, and that's a great, great problem to have."
Max Purcell, Alex Bolt and wildcards Dane Sweeny and Adam Walton all reached the second round.
Purcell was leading No.2 seed Marco Cecchinato 6-2 3-2 when the Italian retired while Bolt made light work of Renzo Olvio, taking an hour to beat the Argentine 6-1 6-2.
Walton swept aside Spaniard Pablo Andujar 6-1 6-2 and Sweeny beat Vit Kopriva 6-1 6-1.
In the opening round of women's qualifying, Destanee Aiava easily accounted for Ipek Oz 6-3 6-3 while Zoe Hives beat Harmony Tan 6-2 5-7 6-1.
But Arina Rodionova suffered a tough loss to veteran American CoCo Vandeweghe, going down 6-4 7-6 (10-8).
Wildcard Seone Mendez was knocked out by Elena-Gabriela Ruse in three sets 6-1 3-6 6-1, Lizette Cabrera lost 6-2 6-3 to Elina Avanesyan and Kaylah McPhee was thrashed 6-4 6-0 by Cristina Bucsa.
American Ashlyn Krueger knocked out former Wimbledon finalist Eugenie Bouchard, winning 6-3 1-6 6-4.
