Aaron Cruden comes in for All Blacks vice-captain Dan Carter who has suffered a hamstring injury which has made him unavailable for selection.
There are two other changes in the backs - last weekend's wingers Zac Guildford and Julian Savea are replaced by Hosea Gear and Ben Smith respectively.
New cap Beauden Barrett has been added to the replacements bench with Tamati Ellison also brought in as cover for the outside backs.
In the forwards, the 26-year-old Romano will make his Test debut in the second row, replacing Brodie Retallick who is on the bench. All Blacks captain Richie McCaw moves to number 8 to cover for Kieran Read who is out with concussion.
Sam Cane gets his first Test start and fellow flanker Liam Messam, who was called into the All Blacks squad this week, is on the blindside, while Adam Thomson is listed among the reserves along with the returning Keven Mealamu.
NEW ZEALAND Team & Replacements (v Ireland, Steinlager Series, Waikato Stadium, Hamilton, Saturday, June 23, kick-off 7.35pm local time/8.35am Irish time):
15 - Israel Dagg (Crusaders)
14 - Ben Smith (Highlanders)
13 - Conrad Smith (Hurricanes)
12 - Sonny Bill Williams (Chiefs)
11 - Hosea Gear (Highlanders)
9 - Aaron Smith (Highlanders)
1 - Tony Woodcock (Blues)
2 - Andrew Hore (Highlanders)
3 - Owen Franks (Crusaders)
4 - Luke Romano (Crusaders)
5 - Sam Whitelock (Crusaders)
6 - Liam Messam (Chiefs)
7 - Sam Cane (Crusaders)
8 - Richie McCaw (Crusaders) (capt)
16 - Keven Mealamu (Blues)
17 - Ben Franks (Crusaders)
18 - Brodie Retallick (Chiefs)
19 - Adam Thomson (Highlanders)
20 - Piri Weepu (Blues)
21 - Beauden Barrett (Hurricanes)
22 - Tamati Ellison (Highlanders)