Horacio Agulla replaces Lucas Gonzalez Amorosino on the right wing and veteran centre Felipe Contepomi comes in for Santiago Fernandez at inside centre.
Amorosino and Fernandez drop to the bench for the final-round fixture between teams separated by two points and seeking to avoid the southern hemisphere tournament’s wooden spoon.
The rest of the team that faded after half-time to lose 33-15 against New Zealand last weekend were given a vote of confidence by coach Santiago Phelan.
“Horacio and Felipe are great players with a lot of experience,” Phelan told reporters as he justified the two alterations.
Argentina are seeking a first Championship victory and many Pumas supporters believe the Wallabies are vulnerable after four losses in five outings.
“We did some great things against New Zealand, especially during the first half, and I remain hopeful of victory this weekend.
“Australia are the third best team in the world with a lot of fast, agile players, and we must be prepared for a difficult challenge,” added Phelan.
The Rosario Test will be the ninth between the teams in the South American country with the Wallabies winning four and Los Pumas three.
15-Juan Martin Hernandez, 14-Horacio Agulla, 13-Marcelo Bosch, 12-Felipe Contepomi, 11-Juan Imhoff, 10-Nicolas Sanchez, 9-Martin Landajo; 8-Juan Manuel Leguizamon, 7-Pablo Matera, 6-Juan Fernandez Lobbe (captain), 5-Patricio Albacete, 4-Julio Farias Cabello, 3-Juan Figallo, 2-Eusebio Guinazu, 1-Marcos Ayerza
Substitutes: 16-Agustin Creevy, 17-Nahuel Lobo, 18-Juan Pablo Orlandi, 19-Manuel Carizza, 20-Benjamín Macome, 21-Tomas Cubelli, 22-Santiago Fernandez, 23-Lucas Gonzalez Amorosino