New Zealand head coach Ian Foster says he has told his players not to "go into your shell" for Saturday's Rugby World Cup quarterfinal with Ireland as "we don't want to die wondering" what might have been.

The three-time champions thrashed the Irish 46-14 at the same stage four years ago but many expect the roles to be reversed at the Stade de France.

The Irish are bidding to become the third Tier One nation to win 18 successive tests – a run that began when they won the final two matches against the All Blacks in their historic series win last year in New Zealand.

Foster, though, like his players, has shown a certain resilience through a mixed set of results since 2019 which resulted in question marks over his job.

The 58-year-old is still there, however, and his side have sparkled in their final three pool matches albeit against mediocre opposition in the shape of Namibia, Italy and Uruguay, having lost their opener to hosts France.

"I've probably already given them my final message," he said at the eve-of-match press conference.

"I just think trust themselves, trust the work we've done as a group and trust the work we've done on the field and off the field and go out and express yourself.

"Quarterfinals, we don't want to die wondering, you don't want to go in your shell, you still want to play our game and it's important to us that we do."

Much has been made of Joe Schmidt, Andy Farrell's predecessor as Ireland head coach, being the All Blacks attack guru and how his insight from his days in Ireland could aid New Zealand.

Foster, though, played that down.

"It hasn't been heavily loaded towards his insight into Irish rugby," Foster said of Schmidt's contribution since he came on board in 2022.

"In a funny old way, when you get into the play-offs, it's actually become more and more about us than probably what you think.

"And I am sure Ireland are the same. They've got a lot of belief in their game, we've got a lot belief in ours.

"I am sure there will be some mixed emotions for Joe in some ways.

"He's very passionate, he loved his time in Ireland and it was a very special time for him.

"But he's loving his time in this team too and we're enjoying having him."

Foster said he had full belief in his players and he entered the game in a relaxed frame of mind.

"I am always relaxed when we've prepared well and we have," he said.

"I enjoyed watching the players prepare this week, they're keen. We know what's ahead of us, I can't wait."