Australia coach Tim Sheens has opted to rest star players Greg Inglis and Matt Scott against Ireland due to niggling injuries, while Johnathan Thurston and Darius Boyd will also take it easy ahead of next week's quarter-final.
Inglis (knee) and Scott (finger) are carrying minor injuries and the Kangaroos are not taking any chances heading into Saturday night's game at Thomond Park in Limerick.
Sheens said it was a great opportunity to give the pair a rest, but said there was no doubt they would be picked the following week for the quarter-finals.
"Inglis has had two full games and the knee is a little sore," Sheens told NRL.com.
"We opted to rest him this week, but there are no major problems, he will be back next week.
"Matt Scott – we are resting him with that finger, he has a little bit of a problem there, so we pushed Gallen up front, he had some really good go forward last week and we need that experience to start the game.
"Scott will be fine, it's just a good chance to give his finger an extra week to recover
"We have a few niggling injuries and a few players we want to make sure are right, so I've named an extended bench and we won't finalise that until later in the week."
Sheens has had several meetings with his side and has reinforced that a good performance against Ireland could help the fringe players force their way into the team for the bigger matches of the World Cup.
It is believed the Australian team still has a few positions up for grabs, with the backline not settled and a place in the back row now up for grabs after the injury of Luke Lewis.
"After this week we will be sitting down and assessing everybody's form heading into the quarter finals," Sheens said.
"Once we know who we are playing, we'll have a look at our performances in each of the three games and try to pick our strongest side based on form.
"I'm really keen to have a good 80 minute performance against Ireland, we owe them that respect."
The Australian team to play Ireland:
1. Billy Slater
2. Jarryd Hayne
3. Brent Tate
4. Josh Morris
5. Brett Morris
6. Daly Cherry-Evans
7. Cooper Cronk
8. Paul Gallen
9. Cam Smith (c)
10. James Tamou
11. Greg Bird
12. Sam Thaiday
13. Nate Myles
14. Boyd Cordner
15. Robbie Farah
16. Andrew Fifita
17. Corey Parker
18. Josh Papalii
19. Johnathan Thurston
20. Michael Jennings