Australia's 31-man squad will be pushed to the limits this weekend against Wales after Adam Ashley-Cooper revealed the Wallabies could be without Israel Folau, Rob Horne and Matt Giteau.

The two-time Rugby World Cup champions booked their place in the knockout stages of the 2015 competition with a 33-13 win over hosts England last Saturday, and their clash with Wales will determine who finishes top of Pool A.

Wales have also struggled with injuries during the tournament, and the Wallabies could be forced into changes in the backs with Folau (ankle), Horne (shoulder) and Giteau (ribs) all major doubts.

"It is something we really haven't had in a long time," Ashley-Cooper told the Sydney Morning Herald. "We are going to be tested this weekend.

"There are question marks around Izzy [Folau] and his ankle, Rob Horne and his shoulder, Gits [Giteau] didn't train this morning because of his ribs, I am sure he'll be right.

"But we are now calling on those guys who have been waiting patiently. They certainly have the talent to start Test match football and we will be relying on them to start this weekend.

"We have got the depth to cover. Matty Toomua is a great defender, Tevita [Kuridrani], myself, we can always reshuffle and work as a midfield combination there."