Midfielder Nonu, back at the Blues after a season at the Highlanders, and loose forward Kaino, who has returned after two years in Japan, will bolster the home side's bench as they look to kick-start their season following two defeats in South Africa.
Neither player went to the Republic, with Nonu working on his fitness following ankle surgery and Kaino preparing for a return to Super Rugby after two years playing for Toyota.
"They just haven't played any footy," Kirwan said when asked why they weren't starting. "One has been in Japan and the other one hasn't played. To run out at this level is a bit like Kevvy [Mealamu] and Woody [Tony Woodcock] a couple of weeks ago. You just can't expect them to start, and so the following week they'll be available full on. That's the strategy we have used and we'll stick to it.
"They are ready to play. Ideally we'll get them out for the last 30 minutes and then they'll be full on into it."
The Blues have been looking for more strength in the midfield since Francis Saili's foot injury and Nonu could be just the man to provide it. Kaino, too, will have an important role to play in adding steel to the forward pack.
Asked what he wanted to see from Kaino, one of the best loose forwards at the last World Cup, Kirwan said: "I hope he brings Jerome Kaino, that's all I've asked him to do. A hard edge, real good physicality and hard ball carrying. We want to get the Jerome Kaino who left New Zealand a couple of years ago back as quickly as possible. He's been fantastic while we've been away, he's worked really hard, so we're expecting him to deliver that from day one and I'm sure he will."
Kirwan said of his team's efforts over the past few weeks: "We need to make sure that we are excited off the football and running. I think if we are missing one thing it's a little effort so we're looking for more effort this week and making sure we're playing for each other."
Hooker Mealamu is unavailable due to his calf injury, with lock patrick Tuipulotu out with a knee injury. Wing Tevita Li's problem hand is not been broken, Kirwan said.
- By Patrick McKendry of APNZ
