The Kiwis coach Gordon Tietjens swapped training tips with United boss Sir Alex Ferguson at the club's Carrington training ground.
"I was very impressed. It is a very good facility and I managed to have a good yak to Alex Ferguson about their training regimes," said Tietjens.
David Beckham, Rio Ferdinand and Ruud van Nistelrooy were among the United players who met the All Blacks.
"They were all brilliant to talk to. Beckham was quite superb. He also has this amazing training ethic and works really hard," added Tietjens.
"They were also quite interested in our training and Alex said he was surprised at the rugby players' physiques and how big they were.
"I also talked to him about the requirements he had as a coach.
"He really does expect the players to put in the hard yards on the training pitch, much like I do."
The All Blacks begin the defence of their 1998 title in the first pool rounds next Friday.