There are a number of changes to the side that started in Melbourne starting in the front row where Jack McGrath and Sean Cronin will partner Tadhg Furlong.
In the second row James Ryan and Devin Toner pack down again while the backrow has a new look with Jack Conan coming in at Number 8, CJ Stander switches to 6 while Peter O'Mahony moves to 7.
The half backs pairing of Conor Murray and Johnny Sexton are joined in midfield by Aki and Robbie Henshaw.
Jacob Stockdale comes back into the back three alongside Keith Earls and Rob Kearney.
The uncapped Ross Byrne is named in the replacements as is Tadhg Beirne, who made his debut last week. John Ryan and Niall Scannell are the front row reserves while Jordi Murphy is also named.
Kieran Marmion and Jordan Larmour complete the bench.
Ireland Team & Replacements (v Australia, Allianz Stadium, Sydney, Saturday, June 23, 8.05 pm local time/11.05 am Irish time)
15. Rob Kearney (UCD/Leinster) 85 caps
14. Keith Earls (Young Munster/Munster) 69 caps
13. Robbie Henshaw (Buccaneers/Leinster) 35 caps
12. Bundee Aki (Galwegians/Connacht) 8 caps
11. Jacob Stockdale (Ballynahinch/Ulster) 10 caps
10. Johnny Sexton (St Mary's College/Leinster) 75 caps
9. Conor Murray (Garryowen/Munster) 66 caps
1. Jack McGrath (St Mary's College/Leinster) 49 caps
2. Sean Cronin (St Mary's College/Leinster) 62 caps
3. Tadhg Furlong (Clontarf/Leinster) 25 caps
4. Devin Toner (Lansdowne/Leinster) 59 caps
5. James Ryan (UCD/Leinster) 10 caps
6. CJ Stander (Shannon/Munster) 25 caps
7. Peter O'Mahony (Cork Constitution/Munster) 49 caps captain
8. Jack Conan (Old Belvedere/Leinster) 8 caps
16. Niall Scannell (Dolphin/Munster) 8 caps
17. Cian Healy (Clontarf/Leinster) 80 caps
18. John Ryan (Cork Constitution/Munster) 14 caps
19. Tadhg Beirne (Scarlets) 1 cap
20. Jordi Murphy (Lansdowne/Leinster) 22 caps
21. Kieran Marmion (Corinthians/Connacht) 22 caps
22. Ross Byrne (UCD/Leinster) uncapped
23. Jordan Larmour (St Mary's College/Leinster) 5 caps