New Zealand all-rounder Chris Cairns might miss tomorrow's day-night cricket match against Australia at the MCG because of concerns about a back injury.

The home side, which would almost certainly drop out of finals contention in the tri series with a loss, will bring in paceman Brett Lee and allrounder Ian Harvey for Jason Gillespie and Andrew Symonds.

Black Caps captain Stephen Fleming said Cairns was receiving intensive physiotherapy today on a disc problem.

The Kiwis will either rest or play their star player, rather than use him as a specialist batsman.

"He's probably ginger, would be the best word to describe it, certainly backing up yesterday was a tough ask and he probably suffered a little bit with his bowling," Fleming said.

"We'll be cautious with him, while there's 24 hours to starting time I'm not willing to commit whether he'll be playing or not.

"There's work to be done and time to be taken - we'll use it."

When asked whether Cairns needed rest, Fleming replied "absolutely", but added the issue was when he should take some time out.

Had New Zealand beaten South Africa last night in Adelaide, Cairns would definitely miss tomorrow's match.

Fleming said his side would be "conservative" with its selection tomorrow, but indicated Dion Nash would probably return.

Australia will go into tomorrow's match on the bottom of the series table behind the competition-leading Kiwis and South Africa.

Each side has two matches to play before the finals start here on February 6. Australian captain Steve Waugh and his team-mates had last night off to refresh after Saturday's 77-run loss to New Zealand in Adelaide.

Waugh said he was impressed with this morning's team meeting and a spirited training session at the MCG, promising a much better effort tomorrow against the Kiwis.

Keen to tone down constant debate about why the team is not playing well, Waugh also played down the significance of the team changes.

"It's just a matter of picking the side, I don't want to get too complicated in it - alternative rotation, alternative injury, alternative form thing - we're just picking 11 players, we'll keep it simple," Waugh said.

Harvey has played only two of Australia's matches in this series, but Waugh said the talent known as "Freak" had the potential to belong at this level.

"He's just got to back his ability - he's a great player and a great talent," Waugh said.

"There's no reason he shouldn't do well at this level, his bowling has been excellent over the last 12-18 months and he's done some good things with the bat."

Waugh is confident the out-of-sorts Australians can regain their touch tomorrow and still make the finals.

"We know we can turn it around, you'll see a side out there tomorrow desperate to win, but relaxed as well and confident in its ability," Waugh said.

"If we don't win tomorrow, we're not good enough - I can accept that as long as we go out there fighting and playing hard.

"I don't mind losing as we go down to the wire."

Squads:

Australia: Steve Waugh (capt), Michael Bevan, Andy Bichel, Adam Gilchrist, Ian Harvey, Brett Lee, Damien Martyn, Glen McGrath, Ricky Ponting, Shane Warne, Mark Waugh. Jason Gillespie or Andrew Symonds 12th man.

New Zealand from: Stephen Fleming (capt), Andre Adams, Shane Bond, Nathan Astle, Chris Cairns, James Franklin, Chris Harris, Brendon McCullum, Craig McMillan, Dion Nash, Adam Parore, Scott Styris, Daniel Vettori, Lou Vincent (team, 12th man to be named).

© 2002 AAP