No tries were scored in the first half with the sides locked 2-2 at half time, but the Kiwis took charge after the break as Jamayne Isaako and Corey Harawira-Naera crossed over.
Daryl Clark replied late on, but Great Britain would fall short and suffer a second loss at the start of the 2019 tour, having lost to a Tonga Invitational XIII last weekend.
It was a scrappy opening 40 minutes in Auckland, with both teams struggling for creativity. Isaako landed the first blow with a penalty goal, but New Zealand lost Kieran Foran to a dislocated shoulder on his return to international rugby after a two-year absence.
Gareth Widdop levelled the scores for Great Britain, but defence ruled a first half of few attacking moments.
— NZ Rugby League (@NZRL_Kiwis) November 2, 2019
The Kiwis improved after the break, though, and it was Roger Tuivasa-Sheck who made the crucial break as he beat two opponents and drew additional tacklers, before flicking over for Isaako to score in the corner.
Briton Nikora's try was ruled out for a knock-on, but Harawira-Naera barged over the line soon after to extend the lead to 10 points midway through the half.
Time was running out for Great Britain but Clark's score with 12 minutes to play gave the visitors hope of completing an unlikely comeback.
Widdop added the conversion and the opportunity to win nearly arrived when Jermaine McGillvary dived over with four minutes to play. But Kenny Bromwich dislodged the ball in the tackle and New Zealand held on to claim victory.
Photo N/A Caption: New Zealand rugby league players