The Welsh XV had plenty of possession to win the game but did not break the gainline often enough up front or run strongly and directly enough behind.
The Welsh forwards more than held their own but behind the scrum it was the tourists who had the edge in both pace and penetration.
Two of the threequarter line, centre Luke McAlister and wing Joe Rokocoko, played in the under-19 side that won the Junior World Cup in Chile last year and they looked the class players of the night.
Rokocoko made the first try with a powerful blindside surge and well-timed pass to supporting scrum-half Scott Cowan to give New Zealand a 7-6 lead, McAlister kicking the conversion.
Cardiff fly-half Nick MacLeod had kicked two penalties to give Wales a 6-0 lead and his third just before half-time put Wales into a tenuous 9-7 lead at the interval.
McAlister kicked New Zealand back into the lead with a penalty before replacement wing Tony Koonwaiyou dramatically snatched the ball out of the grasp of Llanelli full-back Ceiron Thomas to sprint clear for a try converted by McAlister.
Wales threatened but handled sloppily in the face of aggressive defence. The forwards with hooker Huw Bennett (Swansea) and No 8 James Malpas (Cardiff) continued to make a real game of it.
Wales: Pens - N MacLeod (3). New Zealand: Tries - S Cowan, T Koonwaiyou; cons - L McAlister (2); pen - McAlister.
New Zealand Schools will face Welsh Schools U18 at Neath RFC on Friday 18 January. The match kicks off at 7.15pm
The WRU's Women and Girls legacy events - #TRY OUR GAME have proved popular this week with current players and newcomers to the game learning new skills and picking up tips from national squad players.
We caught up with Shona and Ellie from the Wales women team ahead of the start of the Women's Rugby World Cup in Paris next month at a recent women's training session to encourage and promote more women and girls to try their hand at rugby. #tryourgame
The Women's Rugby World Cup warm-up clash between Wales and USA proved bittersweet for centre Elen Evans. Despite being one of the star performers on the day on her 50th Test appearance, USA edged home 10-7 at Cross Keys.
Wales completed their Junior World Championship campaign with a victory over Samoa. Team manager Mark Taylor and No 8 James Benjamin reflect on a tournament which saw Wales win three games and lose two.
Wales U20 players Angus O'Brien, Nicky Thomas and coach Richard Hodges are determined to finish their Junior World Championship with a flourish when they tackle the big hitting Samoans tomorrow in Auckland.