Hamilton on Thursday.
The victory, courtesy of Ahmed Shehzad's 115 and a polished bowling performance gave Pakistan an unassailable 3-1 lead in the series, with only the final match to be played at Eden Park in Auckland on Saturday.
Pakistan made a below-par 268 for nine, but New Zealand wasted a golden opportunity to level the series with only Martin Guptill (65) and stand-in captain Ross Taylor (69) posting any scores of substance in their 227 all out in 46.5 overs.
The hosts had looked well set to push for victory when Taylor was batting with James Franklin in the 42nd over, but when Taylor, who had survived a confident leg before appeal by Shahid Afridi, was given out in the same over their run chase disappeared.
New Zealand have now lost 14 of their last 15 completed one-day internationals.
Pakistan's innings had been anchored by Shehzad's first one-day international century, which he brought up with a push to square leg after he wandered across his stumps to well outside off to give himself some room.
His century came off 101 balls, with 11 fours and two sixes, and the 19-year-old looked to increase the scoring rate even further once he reached the milestone but was caught in the deep by Franklin off Scott Styris in the 38th over.
The visitors had looked well set to push on to 300-plus on a good pitch with short boundaries and while several batsmen got starts, New Zealand's bowlers varied their pace and length to restrict the scoring in the final few overs.
<!--<iframe src="http://www.facebook.com/plugins/recommendations.php?site=www.geosuper.tv&width=480&font=sego e%2Bui" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:480px; height:300px;" allowTransparency="true"></iframe> -->