Former premiership coach Shane Flanagan said Australia's forwards should be Kevin Walters' priority after the Kangaroos struggled physically against Fiji.
Australia beat Fiji 36-22 on Sunday, but its reshuffled pack was outmuscled by the Fijians. Isaah Yeo and Liam Martin were rested, while Tino Fa'asuamaleaui started on the bench.
"I think last night's performance is just where we're at," Flanagan told SEN.
He argued that fullback selection mattered less than winning the forward battle, saying Australia needed to dominate the ruck and improve its line speed.
Attention has also turned to the right edge, where Fiji's Kurt Donohoe created several tries. Hat-trick scorer Tom Trbojevic and centre Kotoni Staggs endured a difficult defensive outing.
Former NRL player Moses Mbaye called for Latrell Mitchell to return at centre, despite Mitchell usually playing on the left for South Sydney.
"I'd bring Latrell Mitchell back in," Mbaye told SEN radio on Monday. "He's one of those guys that can handle it, he's an elite athlete and an elite centre of the game... (and) I'm picking Latrell Mitchell and Bradman Best in the centres. I think we get caught up in this left side/right side thing all the time. With those two guys and especially Latrell, he can play anywhere."
Walters used only three interchange players against Fiji, leaving Mitchell, Reece Walsh and Harry Grant unused. Calls are growing for Australia to field its strongest team against the Cook Islands next weekend and build combinations before the semi-finals.
Mbaye also favoured Walsh over James Tedesco at fullback, and backed North Queensland captain Tom Dearden to partner Cameron Munster ahead of Sam Walker.
Walters said he was "pretty clear" about his preferred halves pairing, but had not announced it. "I feel like we've got to get the best combinations happening and what's best for the team," he told Sky Sports Radio. "I've got some strong ideas and I'll just speak to a couple of the senior players to confirm."