What a difference 24 hours makes.

New Zealand hadn't beaten Australia in a women's fixture of any format since 2016 but the drought came to an end on Saturday night as the Kiwi Ferns stunned the Jillaroos with a 17-15 win in the World Cup 9s final at Bankwest Stadium.

Dominated by the Jillaroos 22-8 in the opening round of the tournament a night earlier, a late try to Nita Maynard from close range was enough for the Kiwi Ferns to edge ahead in the see-sawing contest.

Tensions were felt when Jules Newman crossed the line with the rugby union convert pointing at counterpart Isabelle Kelly, before clashing with Jess Sergis in the shadows of full-time.

It was an emotional victory for Kiwi Ferns captain Honey Hireme, who made her return to the game in the tournament after losing her mother Caryn to cancer in September.

"The last time I won a World Cup was 2008 for the 13-a-side game so to be a World Cup winner again is surreal, to be honest," Hireme told NRL.com moments after the final.

"We woke up this morning with the idea of just flushing that first game, it was the first time playing 9s for most of our girls.

"I think what we showed is that 9s can be an individual game but when you play as a team you win the big one."

Kiwi Ferns playmaker Raecene McGregor crossed the line with a strong individual effort early and was later named player of the tournament.

For the Jillaroos, who went into the final as favourites, the loss would've sent shockwaves through the camp after a dominant campaign.

Jillaroos winger Tiana Penitani finished the tournament as leading tryscorer with five tries, while outside backs Shakiah Tungai and Corban McGregor enjoyed strong personal outings over the two days.

"It was disappointing. The girls had an outstanding week, except for the final," Jillaroos coach Brad Donald said.

"You make a couple of mistakes in this 9s concept, and you pay the price. The Kiwis Ferns just outplayed us in the final.

"Both teams were fatigued but they moved the ball around very well which further fatigued us.

"On the back of us turning the ball over three or four times and that’s an extra three sets you've given away – you just can’t afford to do that in this format."

Earlier, the Jillaroos and Kiwi Ferns booked their spot in the final with two victories apiece on Saturday.

Australia dominated England 42-4 before backing up less than three hours later to beat Papua New Guinea 30-6.

New Zealand bounced back from defeat to the Jillaroos in the opening round with a 24-12 win over the Orchids, followed by a 33-4 win over England.

Hireme and Krystal Rota scored twice in the sudden-death win against the Lionesses to ensure a rematch with the Jillaroos was on the cards ahead of next week's Test match.

The highlight for the Lionesses came in their second-round loss over the Jillaroos with England speedster Kelsey Gentles running down a tiring Tiana Penitani, who picked up a loose ball and sprinted 99 metres down field before being tackle a metre out from the try line.

"It was a good feeling but just a shame about the scoreboard," Gentles said of the 9s experience.

"In these games when you're chasing the scoreboard you've got to put your all into it and I just had a bit more left in the tank. It was all heart but we fell short of what we wanted to achieve today."

Meanwhile, for the Orchids, who went winless in the tournament, their leading try-scorer Ua Ravu said the opportunity to play against some of the best women's players in the world had left an impact on her side.

"It was exciting but nerve-wracking playing a lot of these girls who are NRLW reps – daunting but rewarding," Ravu said.

"It was a hot day but the atmosphere keeps you going on the field when you hear the cheering and big hits.

"We watch a lot of the women on TV so to play them will do a lot for our experience playing back home and in other competitions."