In the centre Jonathan Davies is back to partner Jamie Roberts, taking over from his Scarlets colleague Scott Williams who drops to the replacements bench.
Up front, Dan Lydiate has recovered from an ankle injury to get the nod at blindside flanker over Ryan Jones, who also provides cover from the bench.
The final change comes in the second row where Alun Wyn Jones comes in to partner Luke Charteris, with Bradley Davies again retained as a replacement.
Stephen Jones has missed out on selection in the matchday 22. James Hook has proven his fitness and will provide cover for the backs along with Lloyd Williams and Scott Williams.
Wales head coach Warren Gatland said: "This was a tough selection for us, probably one of the longest selection meetings we have ever had, where we went through every possible permutation available to us.
"It's a great position to be in when you are struggling to find a place for players in the squad and the starting line-up, instead of having to think who can make up the numbers, which has sometimes been the case.
"We believe it is the side which gives us the best chance of winning this game against an Ireland team which not only topped their pool but beat the Wallabies on the way."
WALES Team & Replacements (v Ireland, 2011 Rugby World Cup quarter-final, Wellington Regional Stadium, Saturday, October 8, kick-off 6pm local time/6am Irish time):
15 - Leigh Halfpenny (Cardiff Blues)
14 - George North (Scarlets)
13 - Jonathan Davies (Scarlets)
16 - Lloyd Burns (Newport Gwent Dragons)
17 - Paul James (Ospreys)
18 - Bradley Davies (Cardiff Blues)
19 - Ryan Jones (Ospreys)
20 - Lloyd Williams (Cardiff Blues)
21 - James Hook (Perpignan)
22 - Scott Williams (Scarlets)