Ospreys are without Lee Byrne (foot) and Justin Marshall (shoulder), plus nine players on Wales duty on Saturday.
Brent Cockbain is also missing after a 20-day ban for stamping, while Paul James captains the side from prop.
Both Marshall and Byrne suffered slight knocks in last weekend's Heinelen Cup loss against Stade Francais and should recover soon.
Jason Spice takes the scrum-half role in the absence of fellow New Zealander Marshall, with Shaun Connor at fly-half.
Connor has recovered from an elbow knock, while and back-rower Andy Lloyd has overcome a medial ligament problem to take his place on the bench.
Ospreys: Stefan Terblanche; Richard Mustoe, Sonny Parker, Tal Selley, Jonathan Vaughton; Shaun Connor, Jason Spice; Paul James (capt), Barry Williams, Andrew Millward, Mike Powell, Lyndon Bateman, Lee Beach, Richard Pugh, Filo Tiatia.
Replacements: Huw Bennett, Cai Griffiths, Mike Collins, Andrew Lloyd, Martin Roberts, Andrew Bishop, Nikki Walker.
Australia: Cameron Shepherd; Scott Staniforth, Adam Ashley-Cooper, Gene Fairbanks, Morgan Turinui; Mark Gerrard, Brett Sheehan; Nic Henderson, Tatafu Polota-Nau, Guy Shepherdson, Al Campbell, James Horwill, Hugh McMeniman, George Smith (capt), David Lyons.
Replacements: Stephen Moore, Benn Robinson, Mark Chisholm, Stephen Hoiles, Josh Valentine, Mat Rogers, Clyde Rathbone.