New Zealand survive early scare to open home World Cup with a win
Three quick tries had the Wallaroos dominating the Pool A clash at 17-0 up inside the first half an hour and it was only when the Australians were reduced to 13 women early in the second half that the home side were able to edge ahead.
Prolific winger Portia Woodman scored a hat-trick and her fellow Sevens standout Ruby Tui grabbed a late double as the five-times world champions scored seven unanswered tries to seal what was ultimately a comfortable win.
"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."
Australia, who had never beaten the Black Ferns in 22 previous attempts, started as if determined to spoil New Zealand's party with winger Bienne Terita crossing twice in the right corner after running around the home defence.
In between Terita's tries, her fellow winger Ivania Wong picked up a loose pass and raced 60 metres to score to silence the crowd of more than 35,000.
Lock Joanah Ngan-Woo finally got the Black Ferns on the board with a bulldozing run just after the half-hour mark and two tries from Woodman in 11 minutes around the break tied the scores up at 17-17.
The match turned decisively in the 53rd minute, when Wong and Australia captain Shannon Parry were shown yellow cards within a few seconds of each other.
Before the two Australians returned, replacement prop Awhina Tangen-Wainohu had forced her way over the line to secure New Zealand a bonus point and Woodman bagged her third try.
Tui's late show with two classic winger's finishes was more what New Zealand fans had expected as the Black Ferns look to defend their title from England and France.
The rising European powers earlier got their campaigns off to winning starts at the same stadium, France beating South Africa 40-5 and favourites England crushing Fiji 84-19.
The crowd for the triple-header was a record for a women's World Cup match and for a standalone women's sporting fixture in New Zealand.