The 22-year-old impressed at outside half for the Super 14 semi-finalists and the unbeaten Junior All Blacks in 2007.
Prop Ben Franks, a Crusaders and Junior All Blacks team-mate, and Chiefs flanker Tanerau Latimer have also extended their NZRU contracts until the end of 2010.
NZRU spokesman Neil Sorensen said: "These young players have an important role to play in New Zealand rugby and it is positive and encouraging that they are keen to commit to that future.
"All three have already represented this country with distinction and we look forward to working with them to further develop their talent and potential."
Meanwhile, Latimer's Chiefs team-mate Tasesa Lavea may be ruled out of the entire Super 14 campaign.
The former Auckland fly-half injured an ankle against the Highlanders on Saturday, and initial assessments look bleak for the one-time rugby league international.