The games will be played in Hamilton on June 29, before the first Test, in Wellington on July 12 before the third Test.
McMillan said the Ireland games were massive for the side.
Without disrespecting the sides the Māori All Blacks had played recently, he said Fiji, Samoa and the United States had all been good opposition, but the team had demonstrated historically they had the ability to step up and perform on the big stage.
"Ireland coming out, that's a Tier One nation in the top four of world rankings, and in a purple patch over how they've been performing in recent years.
"So, it's a massive challenge, but one that will be embraced wholeheartedly by the team and the general public," he said.
McMillan said international rugby was played in a congested window with games being organised years in advance and that meant it hadn't been easy for the Māori All Blacks to get games against Tier One nations.
However, there had been a commitment with the games organised that the team retained its important place New Zealand's rugby landscape.
"There's such a proud history, and those who have the fortune of being associated with the team at the moment certainly feel a strong sense of responsibility to make sure that we perform well, and the team is there for future generations," he said.
Ireland would be bringing a team not that wanted to do well on the tour, but also with an eye towards next year's Rugby World Cup.
Bringing an extended squad would allow them to have a look at a number of different players and playing the All Blacks and the Māori All Blacks would present the challenges they were looking for, he said.