A century stand between openers Tamim Iqbal (55) and Imrul Kayes (44) could not save Bangladesh as yet another dramatic collapse saw Bangladesh being restricted to 236 for nine in 50 overs, reports bdnews24.com.
New Zealand captain Kane Williamson (95 not out) then fashioned a colossal 179-run second-wicket stand with Neil Broom (97) and coasted to a facile win with 8.4 overs to spare.
Broom made the visitors pay as he was dropped by Imrul Kayes in the slips off Mustafizur Rahman when he was yet to open his account.
Young seamer Mustafizur (2-32) picked up the two wickets that fell in the New Zealand innings.
But the blame for the loss once again fell on the middle-order batsmen, barring Nurul Hasan, who salvaged some pride in their first overseas tour after two years.
Tamim and Imrul had given Bangladesh the perfect start. In agreeable conditions, the 102-run partnership lay down a solid base for the tourists.
The duo smashed 10 boundaries and a six between them, maintaining a good scoring rate to take Bangladesh past 100 in 21 overs.
A one-handed stunner from Broom took out a wild-slogging Imrul to end the century stand and Bangladesh lost their way.
The middle-order once again fell cheaply, losing seven wickets for 77 runs as New Zealand wiped out the effort of the openers.
A short burst from Sabbir Rahman (19 off 14 balls), another failure from Mahmudullah (3) and a shocking swing of the willow from half-centurion Tamim blew the fine start to bits.
The slide continued as Shakib Al Hasan (18) ran himself out untimely. Youngster Mosaddek Hossain (11) and Tanbir Hayder (3) soon departed, leaving the team teetering on 179 for 7 in 40 overs.
Nurul then showed resolve and launched a late assault 39-ball 44 to give the Bangladesh bowlers a total to bowl at.
For New Zealand, Spinner Mitchell Santner took 2 for 38 and pacer Matt Henry returned 2 for 53. Tim Southee, Jeetan Patel, Jimmy Neesham and Williamson chipped in with a wicket each.
During the chase, the hosts got off to a poor start as left-arm seamer Mustafizur trapped Tom Latham (4) in his first over before Martin Guptill retired hurt with a hamstring issue in an eventful opening spell of the New Zealand innings.
In his next over, the 21-year-old pacer squared up New Zealand's centurion from the last match, Broom and found an edge. But Imrul spilled an easy catch in the first slip.
With Mustafizur and Mashrafe Mortaza on both ends, Williamson and Broom patiently played themselves in.
It was not long before Williamson got in the groove and began stroking the ball majestically to put even the good balls away for boundaries. Broom soon joined the act as the duo forged ahead past 100 in 19 overs.
With the duo easily picking out gaps, they soon shaved the target down to needing less than 50.
Mustafizur who was brought back into the attack struck immediately to end Broom's run-a-ball knock, thanks to a diving catch from Mashrafe in the gully. He studded his innings with 11 fours and a six.
There was a brief pause when New Zealand needed 2 runs to win with Williamson at the non-striker's end on 95, lacing his innings with nine boundaries and a six.
But heeding his captain's advice Jimmy Neesham (28) clubbed a four over long on to wrap it up in style.
Brief scores: Bangladesh: 236-9 in 50 overs (Tamim Iqbal 59, Imrul Kayes 44, Nurul Hasan 44; Matt Henry 2-53, Mitchell Santner 2-38). New Zealand: 239/2 in 41.2 overs (Neil Broom 97, Kane Williamson 95 not out, James Neesham 28 not out; Mustafizur Rahman 2-32)
Bangladesh beat New Zealand by 5 wickets
New Zealand Post 270/8 against Bangladesh
Bangladesh won by 5 wickets
Tri-Series: Bangladesh opt to bat against New Zealand
3rd Match: New Zealand won by 4 wickets
Rain washes out third day of Bangladesh- New Zealand Test in Christchurch
Bangladesh coach Hathurusingha tight-lipped on exclusion of pacer Rubel Hossain
Bangladesh skipper Mushfiqur Rahim blames bowlers after losing Wellington Test
Kane Williamson stars as New Zealand beat Bangladesh by seven wickets
Shakib joins 3000 Club