New Zealand arrive at the World Cup opener with a stronger finals record: nine of their players featured in NRL preliminary finals, compared with three Australians.
Australia's 17 included eight players from the NRL finals series, leaving Andrew Voss concerned about the Kangaroos' form and match fitness.
Chad Townsend also sees a size challenge for Australia against a New Zealand pack led by James Fisher-Harris and Moses Leota.
New Zealand can bring Naufahu Whyte, Erin Clark and Xavier Willison off the bench, while Australia's pack includes Patrick Carrigan, Harry Grant, Tino Fa'asuamaleaui, Liam Martin, Jacob Preston and Isaah Yeo.
Coach Kevin Walters selected a mobile forward group as the tournament adopts NRL rules to speed up international matches.
Townsend said on SEN Radio that Carrigan's starting role surprised him, and suggested Rueben Cotter might have to play in the middle.
He agreed that "the Kiwis have arguably the best forward pack in the world at the moment."
David Riccio raised a separate concern: Australia's backline may struggle to make territory with early carries from its own end.
He said the players were "not necessarily renowned for those tough carries coming out of their own end".
Walters picked Reece Walsh over James Tedesco at fullback, potentially adding speed against New Zealand's bigger forwards.