Jacob Duffy took 4-35 as New Zealand romped to a crushing eight-wicket win in the fifth T20 international against the West Indies on Thursday to seal a 3-1 series victory.

Seamer Duffy removed three batsmen with the new ball as the West Indies collapsed to 21-4 at Dunedin's University Oval before recovering from 48-5 to be all out for 140 in 18.4 overs.

New Zealand made short work of the chase, coasting to 141-2 from 15.4 overs, with opener Devon Conway top scoring with 47 not out including four fours and a six.

After some close, exciting earlier matches, the West Indies' aggressive batting in an attempt to level the series proved too haphazard in seamer-friendly conditions.

Roston Chase top scored with 38 while Romario Shepherd struck a lively 36 off 22 balls in the lower order.

Duffy was named player of the series after taking 10 wickets at an average 12.10.

"We just wanted to be clinical, finish off the series and take it home," said the 31-year-old, who became the first New Zealander to take five four-wicket hauls in T20 internationals.

"We could see there was going to be a little bit in the pitch for us and we did well to restrict a good West Indies team to 140."

New Zealand got off to a flying start racing to 69 off 7.1 overs before Tim Robinson departed for a hard-hit 45, having smacked five fours and three sixes.

The result was almost assured before Rachin Ravindra was next out for 21 to leave New Zealand 106-2 after 11.5 overs needing just 35 for victory.

Mark Chapman joined Conway and hit two sixes to be unbeaten on 21 at the end.

West Indies captain Shai Hope said his team struggled to adjust to the conditions, though he made no excuse for their aggressive approach at the top of the order.

"It was something we spoke about, wanting to put good bowling under pressure and not allowing them to settle too much," Hope said.

"It didn't work out for us this time around. There are pleasing signs but certainly areas we can improve on."

The teams will square up again for three one-day internationals starting in Christchurch on Sunday, followed by three tests in December.