New Zealand Rugby agreed contract extensions with lock Brodie Retallick and prop Wyatt Crockett on Tuesday but second row Anthony Boric opted to join the growing number of All Blacks plying their trade in Japan.

Crockett, 30, and Retallick, 21, have agreed deals to stay with the Canterbury Crusaders and Waikato Chiefs until the end of the 2015 Super Rugby season, making them available to compete in the World Cup later that year in England and Wales.

Their commitment was welcomed by All Blacks coach Steve Hansen.

"Wyatt and Brodie are both quality men and quality rugby players and it's fantastic that they have put their hands up and said 'we want to stay', especially as we know they have the choice to play their footy elsewhere," Hansen said in a New Zealand Rugby statement.

"Their re-signing is great for New Zealand rugby and great for the All Blacks."

Boric, though, has signed a two-year deal with the Mitsubishi Dynaboars and will join the Japanese second tier club from the Auckland Blues in September at the end of the Super Rugby season.

The 30-year-old has been capped 24 times by the All Blacks but is only just returning to action after a year out with a severe neck injury. The chance to move to the lucrative, less physically demanding Japanese league has come at the right time.

"I'm disappointed AB (Boric) is leaving as he is a great player, who I believe still has a lot to offer both the Blues and New Zealand rugby," Auckland coach John Kirwan said.

"However, I have spoken with him and fully understand his decision."

Boric follows fellow All Blacks Richard Kahui and Adam Thomson in making the move to Japan, while Chiefs one-cap winger Lelia Masaga also recently agreed to a deal with Honda at the end of the Super Rugby season.

Flyhalf Stephen Donald, who kicked the winning penalty for New Zealand in the 2011 World Cup final, will join Boric at the Dynaboars after agreeing a switch from English club Bath on Monday.