Beth Mooney (60) and Georgia Wareham (3-17) starred for tournament hosts Australia, who join England, India and South Africa in the final four.

However, they could be without star player Ellyse Perry in Thursday's semi-final after the all-rounder went off injured with an apparent hamstring injury sustained while fielding.

Perry was visibly emotional as she was helped off the field and captain Meg Lanning admitted "it didn't look good" in an interview at the end of the match.

Australia will learn their semi-final opponents on Tuesday. If South Africa beat West Indies in Sydney, they will leapfrog England in Group B and face Australia. If the Windies win, it will be England against Lanning's side.

Hosts hitting form at the right time

Australia's margin of victory was closer than it appeared on the field as New Zealand managed to take the game deep despite always being behind the run-rate and losing regular wickets.

Leg-spinner Wareham was the decisive factor with the ball as she dismissed three of New Zealand's top four.

First she successfully reviewed an lbw decision against Suzie Bates before deceiving both Sophie Devine (31) and Maddy Green (28) and having them expertly stumped by the peerless Alyssa Healy.

Megan Schutt made up for dropping a sitter by taking three wickets of her own in an Australia display which continues their improvement since a shock 17-run defeat by India in the tournament's opening game.

"It was a crunch game and we handled it very well," said Australia captain Lanning. "For Georgia to come in and bowl so well is a credit to her.

"The Bangladesh game (last time out) was a turning point for us. We played a lot more like how we play. We are looking forward to our next challenge.

"We were calm when under the pump and did the basics well. It gives us a lot of confidence going into the semi-final."

Mooney's runs anchor Australia

Desperate to assert themselves in what was effectively a quarter-final, Australia lost the key wickets of Healy (9) and Lanning (21) early on to aggressive shots.

However, Mooney (60) played a classy and stabilising knock which laid the platform for a winning total.

From there, Perry (21 off 15 balls) and Rachael Haynes (19 not out off 8) delivered punchy cameos which took the total beyond 150 and heaped the pressure on the White Ferns.

What was particularly impressive about Australia's batting effort - and was perhaps the difference in a tight contest - was their running between the wickets and ability to cut down on the opposition's ability to bowl dot balls.

"You can always go back over the 120 balls and find something you could do better," said New Zealand captain Sophie Devine.

"Credit to Australia, they're a great team and I wish them well going forward.

"The beauty of this tournament now is that it's hard to pick a winner from the four teams left."