Cardiff Blues chief executive Robert Norster said:
"Xavier is an outstanding player and proven leader of men having guided the Auckland Blues to Super 12 success in 2003. We are thrilled and delighted that he joins us against significant competition from many sides throughout the rugby playing world.
"Besides providing such on-field impact we are confident Xavier will integrate well into Wales and continue the already strong links between our rugby-loving countries."
Cardiff Blues director of coaching, David Young, commenting further, said:
"We have tracked Xavier for some considerable time and linked up with him on our recent trip to South Africa. We had identified his many qualities both as a player and leader and were very keen to complete negotiations for him to join us. He is an extremely focused competitor who has the necessary experience, but is still young man with a tremendous appetite and enthusiasm for the game."
Born :13 July 1977 in Auckland
Height: 6'1" Weight: 16st 9lbs
New Zealand test debut : 1998 v Australia
Captained Auckland Blues to Super 12 victory and Auckland to Ranfurly Shield (both 2003)
Other captaincy experience: Sacred Heart College; New Zealand under-19s; New Zealand Colts; Auckland (NPC)
Most recent international : August 2004 v South Africa