An unbeaten 98 from Alex Carey and a formidable partnership with Mitchell Marsh rescued Australia from a dire position to set up a three-wicket victory in a tense second Test against New Zealand on Monday.

Carey and Marsh put on a vital 140-run partnership at the Hagley Oval in Christchurch, the tourists having had their backs to the wall at 80-5 in their chase of 279.

At 220-5, the Test took another turn when Ben Sears claimed Marsh and Mitchell Starc in successive deliveries, leaving Australia needing a further 59 runs with three wickets remaining.

Australia captain Pat Cummins joined Carey to drag the tourists home, with the winning runs coming from a boundary by Cummins.

It sealed a 2-0 series win for the visitors and earned them valuable points in the World Test Championship standings.

New Zealand were left deflated after starting the fourth day with high hopes of a first home victory over their neighbours in 31 years.

When Australia resumed the day at 77-4, after a one-hour delay because of rain, Marsh on 28 was dropped by Rachin Ravindra in the second over and Travis Head was out on the next ball from Tim Southee.

New Zealand were buoyant, aware that Marsh and Carey were struggling for form, with Marsh coming off back-to-back ducks.

Carey had compiled just 27 from his three previous innings in the series.

The Australian pair found form when it mattered and rather than be cautious, they went on the attack at more than five an over in the morning session as batting conditions became easier with the ageing ball.

The breakthrough New Zealand desperately sought came after lunch when debutant Sears took his double.

Marsh, who had made 80 off 102 deliveries, went lbw and Starc followed first ball caught at square leg by Will Young.

The hat-trick ball, however, was wide of the mark and the new batsman Cummins edged it for four.

Carey had an anxious moment when given out lbw to Matt Henry on 19 but on review the ball tracker placed the ball outside leg stump.

He gave few other chances in a 123-ball innings which included 15 boundaries.

For New Zealand, Sears took 4-90 while Henry's 2-94 gave him nine wickets for the match.