New Zealand also helped Gayle along the way as Daniel Flynn spilled a regulation catch at point when Gayle was on 36 from the bowling of Doug Bracewell.
Some tight bowling from Daniel Vettori and Kane Williamson managed to slow the juggernaut down later in the day, but Powell also chipped away from the other end as the home side showed how easy it could be to bat on the Antigua wicket.
Vettori was able to extract some intriguing bounce from the pitch, while debutant Neil Wagner steamed in throughout the innings and continued to threaten without managing to break through.
All of Vettori's wisdom and experience will be crucial to New Zealand's cause on day three as they need to claim early wickets to try and find a way in to the match.
This match also marks a major milestone for the bespectacled bowling all-rounder, who is playing his 112th test, the most by a New Zealander and he has moved ahead of Stephen Fleming who made 111 appearances.
Earlier, New Zealand resumed day two on 232-4, with night watchman Wagner and Williamson at the crease, but Wagner was quickly sent back to the pavilion as deceptive spinner Sunil Narine claimed his fourth wicket of the innings.
From 233-5, the Kiwis laboured through a string of insignificant partnerships and failed to capitalise on the solid start their top four had provided on day one.
Of the remaining established batsmen, Williamson, Dean Brownlie, Daniel Vettori and Kruger van Wyk all got in to double figures but failed to score more than 23, which greatly damaged New Zealand's chances of pushing past 400.
Only some late blows from No 10 Bracewell, who swatted 39 from 31 balls, saw the Black Caps push up towards a total they could be happy with.
Bracewell and Chris Martin, who has a career batting average of 2.51 in test cricket, put on 42 for the 10th wicket as Martin made four not out and the Kiwis closed their innings on 351.
Narine, who has become a revelation in international cricket in recent months, finished with 5-132 from 43 overs, while Ravi Rampaul and Kemar Roach each picked up two wickets and captain Darren Sammy claimed the other.