Alex Carey scored a magnificent unbeaten 98 to drive Australia to victory over New Zealand by three wickets in a tense conclusion to the second Test in Christchurch on Monday, sealing a 2-0 series sweep for the visitors.

Wicketkeeper Carey combined with Mitchell Marsh in a match-winning partnership of 140 for the sixth wicket and then teamed up with captain Pat Cummins as Australia chased down their 279-run victory target before tea on day four.

"It was pretty tense," said Cummins, who scored 32 not out and hit the winning runs with a four to the point boundary.

"I think the story of this series was in key moments, someone stood up and made themselves a match-winner so yeah, keep finding ways to win. It's a pretty awesome squad."

New Zealand, chasing a first home win over their neighbours in 31 years, had put the tourists on the back foot with four wickets in the last 90 minutes of play on day three.

After rain delayed the start of day four for an hour, skipper Tim Southee struck with the eighth delivery to dismiss Travis Head for 18 and reduce the tourists to 80-5.

In retrospect, however, Rachin Ravindra fumbling a straightforward catch that would have sent back Marsh for 28 off the previous delivery was perhaps the more significant moment.

"I think whenever you've finished a close game you always look back on a number of things," said Southee, who with fellow stalwart Kane Williamson was playing his 100th test.

"This morning was always going to be a crucial period with the ball still reasonably new, and we were able to beat the bat a few times but they were able to weather that storm.

"Obviously, the partnership between Mitch Marsh and Alex Carey just sort of broke the back of our attack."

CROWD SUBDUED

The defeat left the Black Caps with just one test win in 24 attempts against their closest rivals this century, while Australia will now move above them into second place in the World Test Championships standings behind India.

After the early setback, Carey came out to join Marsh and the pair scored at a fair lick, subduing the crowd and gradually putting the pressure on the New Zealand bowlers.

Marsh picked up his ninth test half century and Carey his eighth but both had scares along the way.

Carey kept his wicket by virtue of reviews when he was on 19 and 37, while Marsh was saved on 55 when the technology showed the tiniest bit of bat on a Glenn Phillips delivery that hit him on the toe.

Lunch came and went with the atmosphere flat but the crowd burst into life when seamer Ben Sears (4-90) was brought on and trapped Marsh lbw before having Mitchell Starc caught by Will Young at square leg on successive balls.

Cummins came in to fend away the hat-trick ball, however, and Carey survived another scare when Phillips failed to reach a tough catch that would have given Sears a five-wicket haul on his test debut.

The New Zealand bowlers lacked nothing in effort but edges flashed wide of the cordon and anything on the stumps was blocked as Australia's kept the scoreboard ticking over.

Carey was ultimately denied his second test century but cared little as he and his captain steered their side to their target 281-7 and a sixth win in seven tests over the Australasian summer.

"Although at times we've been a little bit under pressure, we've stayed resilient throughout," said Carey, who also took 10 catches over New Zealand's two innings to match Adam Gilchrist's Australian record.

"Everyone's had their moments and it's a really special team we're playing in."

New Zealand seamer Matt Henry was named Player of the Series for his 17 wickets over the two matches, the first of which finished with Australian victors by 172 runs in Wellington.

"It's disappointing," said Henry. "But at the same time we saw a lot of fight out there and we didn't stop coming in."