The fifth and final match of the tour is a series decider after back-to-back wins for Australia in Wellington this week.

One part of Australia's form revival has been Finch's own batting, contributing fine innings of 69 and 79 not out.

The other has come from the spin duo of Adam Zampa and Ashton Agar.

The pair had just a wicket between them before arriving in Wellington and the spin-friendly drop-in pitch at Sky Stadium.

Yet Agar took Australian record figures of 6-30 on Wednesday, and on Friday, after being handed the new ball, returned 2-11, including 17 dot balls.

On Friday night, Zampa also took two wickets, as did part-timer Glenn Maxwell.

So might there be room for another tweaker when the series goes on the line?

There appears to be one player who could be expendable - Mitch Marsh.

The Western Australian hasn't bowled this series, and hasn't been in the runs since his lone hand in the first-up loss in Christchurch, when he scoring 45 of Australia's 131.

If Marsh is sacrificed, Daniel Sams could return to the side, or Australia could take a risk and throw 19-year-old Tanveer Sangha in at the deep end.

The teenage leggie was the leading Big Bash League spinner and would add another deadly dimension to the Australian attack.

"We will look at every option, no doubt," Finch said.

"No doubt (Sangha) will come up. I love having spinners in the side so that will always be a question that I asked of the selectors and the coach, how can we fit an extra spinner in.

"But the boys are playing nicely and the balance of the side feels really good at the moment."

As he ponders a winning formula for the final T20, Finch heaped praise on his side for recovering the series from 0-2 down.

"It's not the first time that we've done it either in a series when we've been (knocking) on wood from two games. It's a really good character test," he said.

"It's nice to be to be performing well at the business end."

After the praise, the next breath brought a warning that momentum gained from previous matches could only carry them so far.

"T20 cricket is about transferring pressure," he said.

"When you're on the back foot you've just got to find a way to transfer the pressure onto the opposition.

"We've got some guys who do that really well. So have New Zealand.

"You don't take (momentum) into the next game obviously when (Kiwi quicks Trent) Boult and (Tim) Southee have got a brand new ball.

"But maybe it gives our boys a little bit of confidence."

Australian Associated Press