New Zealand reached stumps at 144-4 in reply to England's first innings of 353, on the back foot after the dismissal of captain Kane Williamson for 51 in the final session. Henry Nicholls was 26 not out and B.J. Watling on 6.
Nicholls was struck on the helmet by England's star fast bowler Jofra Archer just before stumps and took time to compose himself before continuing his innings. Archer hadn't been particularly effective for most of the New Zealand innings and ended the day with 0-40 from 14 overs but found some spiteful bounce just before the end.
The first day may have been England's as it reached 241-4 after winning the toss, helped by half centuries from Rory Burns (52), Joe Denly (74) and a developing innings from Ben Stokes, who was 67 not out at stumps.
Stokes went on to 91 Friday, mostly in partnership with Ollie Pope (29), but was the first victim of swing bowler Tim Southee who took three wickets in the space of 11 balls to bowl New Zealand back into the match during the morning session.
Southee also dismissed Pope and Sam Curran, first ball, and took a catch at second slip to remove Archer, reducing England from 277-4 to 295-8 and putting New Zealand briefly in the driver's seat.
But a 52-run partnership for the ninth wicket between Jos Buttler and tall, bespectacled spinner Jack Leach won back lost ground for England and allowed the tourists to reach 353, a competitive total on a slow batting pitch.
New Zealand's first innings progressed in fits and starts as it lost Tom Latham for 9, Jeet Raval for 19 and Ross Taylor for 25 before Williamson fell close to stumps, tipping the balance back in England's favor.
The pitch at Bay Oval, hosting a test match for the first time, favored neither bowlers nor batsmen to any great degree, explaining the fluctuating nature of the second day.
There was swing available at the start of the day when New Zealand began with a ball only 11 overs old and later when Stuart Broad and Curran, for England, floated the ball about with occasional success.
Williamson's loss dealt a major blow to New Zealand's hopes. He looked comfortable in reaching his 31st test half century before receiving a ball from Sam Curran which spat off a length and carried off a glove to second slip.
Several New Zealand batsman could be accused of throwing away their wickets. Opener Raval found himself tied down by England's left-arm spinner Leach, hit out and was caught for 19. Taylor made a solid start in partnership with Williamson but, on 25, misjudged a ball from Stokes and offered a simple chance to Pope.
Williamson looked solid and likely to anchor New Zealand's inning until Curran caused a ball to rise off a length and take his glove in the final twist of the second day.
"I guess it would have been nice to be three down tonight," Southee said. "But we've still got some batting to come and hopefully a couple of good partnerships and we can eke out some more runs. I think we bowled well yesterday and picked up the rewards today. "