All Blacks centre Ma'a Nonu scored 10 minutes into the second half to put New Zealand on course for a 29-9 victory over Six Nations champions Wales at the Millennium Stadium in Cardiff on Saturday.
Blindslide flanker Jerome Kaino scored a second try in the final minutes while flyhalf Dan Carter kicked 19 points.
Three penalties to Stephen Jones to two by Carter gave Wales a 9-6 lead at halftime.
Carter levelled immediately after the interval and Nonu then scored his second try in successive internationals, running on to hooker Keven Mealamu's pass after Carter had spun the ball right.
New Zealand need to beat England at Twickenham next weekend to record their third grand slam of victories over the four home nations.
England earlier lost to the Springboks by a record 42 points to 6 - the home side's worst losing margin at Twickenham.