Perenara will play back-up to Aaron Smith at Aviva Stadium on Monday morning, with seven changes to the starting line-up which beat England 30-22 at Twickenham last weekend.
It will be the All Blacks' final outing of a perfect year so far and they are keen to make history and finish it differently to 2012 when they slumped to defeat against England.
Tony Woodcock's hamstring strain means he has been replaced by Wyatt Crockett at loosehead prop, with Andrew Hore in for Keven Mealamu at hooker and Charlie Faumuina at tighthead prop for Owen Franks. Luke Romano replaces Brodie Retallick at lock, with Steven Luatua in for Liam Messam on the blindside flank the other change to the pack.
In the backs, Aaron Cruden replaces the injured Dan Carter at first-five and Cory Jane comes in for Charles Piutau on the wing. Unsurprisingly, Julian Savea retains his place on the other wing.
Hansen said giving impressive newcomer Piutau a break was a straightforward decision. "This week was pretty easy. We looked at Charles - he's young and when you look at the history of our guys we've usually only given them a couple of big games and then let them step back out and unfrazzle their heads and have a bit of a mental break. He's played four ... the Aussies, Japan and France and England.
"It's bloody stressful preparing for a test match, particularly if they've played very few of them. There's a lot of energy that goes into that.''
Hansen said the five unforced changes were a chance to insert some freshness. Franks, Retallick and Messam have had big workloads this year.
"It's a reflection of the physical nature of the whole year really, particularly the last nine weeks. We've gone around the world twice - this will be our seventh test in nine weeks. We had a big physical game against Argentina, another big physical performance in Jo'burg, a lot of running and chasing [against Australia] in Dunedin [which was] not quite as physical as those other two games.
"France was physical and England was physical. It's just an accumulation of a lot of travel and game time. We've got the ability sitting there that is fresh so why not use them?''
Hansen said he was tempted to rest centre Ben Smith, who is in line to mark veteran Brian O'Driscoll, as the Highlanders player had appeared in 30 matches this year including all 13 tests.
"He's had a massive season. Luckily we've had an extra day this week because that helped.''
Hansen said the challenge for 22-year-old Perenara was to stay as relaxed as possible.
"He was reasonably excited,'' he said of Perenara's reaction at being selected. "He just needs to contain that excitement and use it as a positive manner rather than being a bit like a demented moth around a lamp - don't get too energised and try to do everything at once.''
All Blacks team to play Ireland at Dublin's Aviva Stadium on Monday, kick-off 3am NZT: Israel Dagg, Cory Jane, Ben Smith, Ma'a Nonu, Julian Savea, Aaron Cruden, Aaron Smith, Kieran Read, Richie McCaw (c), Steven Luatua, Sam Whitelock, Luke Romano, Charlie Faumuina, Andrew Hore, Wyatt Crockett. Reserves: Dane Coles, Ben Franks, Owen Franks, Brodie Retallick, Sam Cane, TJ Perenara, Beauden Barrett, Ryan Crotty.