Marshalled superbly by veteran halfback Ali Brigginshaw, who claimed the player of the match award, the Jillaroos registered a 10-try victory - their biggest-ever against their trans-Tasman rivals in 26 Tests.

Try-scoring doubles from centre duo Isabelle Kelly, Jess Sergis and prop Kennedy Cherrington helped Brad Donald's outfit secure victory at Old Trafford on Saturday (Sunday AEDT).

Only Madison Bartlett's second-half effort prevented the Kiwi Ferns from being held to nil in an underwhelming showing.

"They are the greatest bunch of ladies," Donald said.

"I'm ecstatic for the group, it was everything we've dreamt of and spoken about for a number of years.

"We made a lot of mistakes today but we had no concerns we'd put on a good performance."

New Zealand had pushed the Jillaroos all the way in the group stages only to suffer a 10-8 defeat in York but here they barely laid a glove on the Australians.

The Jillaroos' victory meant they drew level with the Kiwi Ferns' haul of three World Cup wins and ensured they haven't lost to their trans-Tasman rivals since 2016.

That pool stage result had given New Zealand hope that they might be able to spring an upset, but Australia got off to an ominous start when Brigginshaw sent Sergis across the line after just five minutes.

The Kiwi Ferns were unable to capitalise on a smart break from captain Krystal Rota and Kelly made them pay when she crashed over on the left with a quarter of an hour played to extend Australia's lead.

The Sydney Roosters' centre did a good job of nullifying the destructive Kiwi right edge of Amber Hall and Mele Hufanga, meaning New Zealand struggled to get out of their own end.

A deft and adventurous kick from Brigginshaw over the top of a tiring Kiwi Ferns' defence found its target, with Brisbane winger Julia Robinson regathering and racing away to score in the corner.

Kelly grabbed her second just before the break to give the Jillaroos a halftime lead of 20-0 and leave their opponents with a mountain to climb.

Utility Emma Tonegato continued the Australians' free-flowing attack and New Zealand's resolve began to crumble.

"We didn't give ourselves a chance, we played our worst game, today we were way off our best," said New Zealand coach Ricky Henry.

"The game has grown so rapidly in Australia and we need to try and get on that train."

Sergis added a second and five-eighth Tarryn Aiken crossed before the hour-mark to put Australia 38-0 ahead.

Bartlett went in at the corner after a nice break from Rota to restore some respectability to the scoreline but the Kiwi Ferns were pegged back by a four-minute double from Cherrington and a smart finish from winger Evania Pelite.

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