A five-wicket haul by Jacob Duffy gave New Zealand a 64-run first-innings lead over the West Indies after the tourists all out for 167 in the first test on Wednesday.
At stumps on day two in Christchurch, New Zealand were 32-0 in their second innings to be 96 ahead. Devon Conway was 15 not out with Tom Latham on 14.
Once the forgotten man of New Zealand domestic cricket, Duffy found himself the enforcer in only his second test.
"There was a point in time I didn't think I would be playing any test cricket," said the 31-year-old, who made his international debut against Zimbabwe four months ago.
"It's my second test, the first at home, and it feels really cool to get a 'five-for'.
"And to put our team in a good position is pretty huge."
In 16 deliveries following a rain break in the final session, Duffy removed the last four West Indian batsmen while conceding only two runs off his bowling.
The fast bowler had earlier dismissed the West Indies top scorer Shai Hope for 56 to finish with career-best figures of 5-34 off 17.4 overs.
Half-centuries from Hope and Tagenarine Chanderpaul provided the backbone of the West Indies innings in a 90-run stand for the third wicket.
TOUGH FOR BATTING
But Chanderpaul said it was difficult to bat on a second-day wicket that continued to be bowler-friendly.
"It was seaming around all day and you just had to try and hang in there," he said.
"You had to pick up singles here and there and score when you could. It was definitely tough."
Hope, wearing sunglasses under heavily overcast skies because of an eye infection, went to the crease with the West Indies in early trouble at 10-2.
Despite being affected by conjunctivitis and needing breaks to be treated with eye drops, he produced a near-chanceless sixth test half-century.
But on 56 he allowed a short ball from Duffy to brush his gloves on its way to wicketkeeper Latham and was gone.
Matt Henry struck twice with a double-wicket maiden having Roston Chase and Justin Greaves caught behind by Latham as the West Indies slumped from 100-2 to 106-5.
Chanderpaul battled his way to 52 from 169 deliveries before he was undone by Zak Foulkes as the floodlights came on under murky skies after the tea break.
The West Indies opener had been dropped twice, on five and 24, by Conway at leg slip.
But Conway, leaping to his left, pouched the third chance sent his way at midwicket.
After a 30-minute rain interruption Duffy removed Tevin Imlach (14), Johann Layne (0), Jayden Seales (2) and Ojay Shields (0).
The West Indies took just three balls to end the New Zealand first innings at the start of the day, without an addition to the overnight score of 231.
Foulkes, the last man out, was then immediately in the action with the ball, removing John Campbell for one with his first delivery.
Will Young completed the dismissal with a smart one-handed catch to his left at third slip, but then dropped a regulation chance when Alick Athanaze, on four, edged Henry.
However, the scoreboard had not moved before Henry bowled Athanaze in his following over with a ball that nipped back sharply.
NEW ZEALAND: Tom Latham (capt), Devon Conway, Kane Williamson, Rachin Ravindra, Will Young, Tom Blundell, Michael Bracewell, Zak Foulkes, Nathan Smith, Matt Henry, Jacob Duffy.
WEST INDIES: John Campbell, Tagenarine Chanderpaul, Alick Athanaze, Shai Hope, Roston Chase (capt), Justin Greaves, Tevin Imlach, Kemar Roach, Johan Layne, Jayden Seales,Ojay Shields