The Australian women's team has never beaten the Black Ferns and was well off the pace last year when the two teams met twice.
In the first test in Sydney, the Black Ferns pulled away to win 31-11.
They backed that up a week later in Auckland, winning 45-17 in a polished performance.
The Black Ferns have spent a week in Perth having a good build-up for the tests.
That follows a four-test series in San Diego last month so the side is starting to find combinations.
Head coach Glenn Moore said the team was excited about the game and getting out in front of a big crowd.
"The players are all working hard to challenge selection and represent their country," he said.
"There's a lot of anticipation around these double-headers with the All Blacks and it will be special to play in Perth's new stadium.
"It's a sellout and we expect there'll be quite a few Kiwis cheering us on. We're looking forward to getting out there on Saturday."
Such is the turnover of the Black Ferns side these days as many players move between sevens and 15s, and others move on, only about half tonight's starting side played in the tests last year.
But there is a still a core of experience with fullback Selica Winiata and halfback Kendra Cocksedge sure to play big roles in the Black Ferns attack.
Coming off the bench will be new players in tighthead prop Olivia Ward-Duin and Otago midfield back Kilisitina Moata'ane, who will looking forward to finally make her test debut.
Up front, captain Les Elder and lock Eloise Blackwell will be important for the Black Ferns as there is a touch of greenness about the engine room.
The Australians had a 2-0 win over the Japanese in a series earlier this season but the Black Ferns will be a much more severe examination.
The home team has brought back props Evelyn Horomia and Liz Patu to solidify the front row.
The game will kick off at 7pm (NZ time), which is the middle of the afternoon in Perth. Fine weather is forecast.
The sides play again at Eden Park next Saturday.
The series is for the Laurie O'Reilly trophy.
Black Ferns v Wallaroos
Perth, today, 7pm
Black Ferns: Selica Winiata, Renee Wickliffe, Carla Hohepa, Chelsea Alley, Ayesha Leti-I’iga, Ruahei Demant, Kendra Cocksedge, Charmaine McMenamin, Les Elder (c), Pia Tapsell, Eloise Blackwell, Aleisha-Pearl Nelson, Te Kura Ngata-Aerengamate, Toku Natua. Reserves: Forne Burkin, Leilani Perese, Olivia Ward-Duin, Joanah Ngan-Woo, Kennedy Simon, Arihiana Marino-Tauhinu, Krysten Cottrell, Kilisitina Moata’ane.
Wallaroos: Mahalia Murphy, Samantha Treherne, Alysia Lefau-Fakaosilea, Ariana Hira Herangi, Lori Cramer, Trilleen Pomare, Georgia Cormick, Grace Hamilton (c),
Emily Chancellor, Millie Boyle, Alisha Hewett, Michaela Leonard, Evelyn Horomia, Averyl Mitchell, Liz Patu. Reserves: Ash Marsters, Emily Robinson, Christina Sekona, Rebecca Clough, Shannon Mato, Iliseva Batibasaga, Arabella McKenzie, Mhicca Carter.
