All Blacks backrow Dalton Papalii has described Joe Schmidt as one of the greatest coaches of all-time.
The former Ireland head coach joined the All Blacks coaching staff last year and was promoted to attack coach 13 months ago.
"He's one of the coaching GOATs in the world," Papalii said on Monday.
"He has a lot of knowledge of the game, especially for me and Mark [Telea] when he came into our Super [Rugby] team [The Blues] last year he was a real difference maker.
"He did wonders for us and coming into this environment he's added his flavour and all the boys can feel it."
The All Blacks play Italy in their third game of the Rugby World Cup on Friday. They have already lost to tournament hosts France and beaten Namibia.
Should Ireland top their group and New Zealand finish second in theirs, the two sides would meet in the quarter-finals. Schmidt's knowledge of the Irish team could prove valuable in that situation.
"Joe has put in a lot of work for us, our backs, our forwards, he's helps us a lot," said All Blacks winger Mark Telea.
"Our ball carries, our contestables, all those little details that other teams or players miss.
"He's massive, I would say Joe knows more than other coaches, hey. He knows the names of players, when he talks about information, he knows a lot of information.
"He would probably even ref the game if he wanted to."
Schmidt's time with the All Blacks will end after the World Cup. He was not named as part of incoming head coach Scott Roberton's backroom team.