Three tries in the first 28 minutes, two of them from Bienne Terita, gave the Wallaroos, who finished sixth in the last edition of this competition five years ago, a 17-0 lead and hope of earning their first win over New Zealand in the 23rd attempt.

But boosted by the support from a 35,000 crowd - a Women's World Cup record - the home team kept their nerve and responded with their own blizzard of tries, of which three were scored by Portia Woodman, who was top scorer at the 2017 Rugby World Cup in Ireland with 65 points from 13 tries.

The Black Ferns thus earned four points for the win and a bonus point for scoring at least four tries to establish themselves at the head of a group that also includes Wales and Scotland, who will meet tomorrow at the other venue being used for this normally quadrennial event, Northland Events Centre in Whangarei.

The ninth edition of this event was originally due to have been held last year but had to be postponed because of COVID-19 restrictions.

"It was definitely a game of two halves," said New Zealand captain Ruahei Demant.

"Australia really put us under the pump there right from the start.

"I’m proud of how we closed off that first half and the way that we finished that game."

Day one also saw earlier opening match victories at Eden Park for the side beaten by New Zealand in the last final, England, and France, bronze medallists in 2017, both of whom also gained bonus points.

France won the first game of the tournament 40-5 against South Africa, and then England ran amok against Fiji to earn an 84-19 victory.

Claudia McDonald scored four of the England tries and Amy Cokayne contributed two more.