Wallabies head coach John Connolly has made wholesale changes to his starting XV with only five players retaining their places after last week's 31-0 victory over Wales in Brisbane.
Fly-half Stephen Larkham, Drew Mitchell, Adam Ashley-Cooper and full-back Julian Huxley remain in the backline, while lock Dan Vickerman is the only forward in this week's starting pack to have played from the outset in Brisbane.
"This Test will be extremely important for the players involved and very important for the team as we look to establish some depth in positions in the build-up to the World Cup," Connolly said.
"We're looking to improve our performances each week and that will be no different on Saturday."
Former skipper Gregan earns his first start at scrum-half since last September's Tri-Nations clash against South Africa in Johannesburg. The 129-cap veteran takes over at number nine in place of Matt Giteau, who is nursing a minor knee injury.
Gregan's promotion sees Reds scrum-half Sam Cordingley make his long-awaited return to the Wallabies squad on the bench.
Phil Waugh is back in the side after starting last week's match as a replacement has been handed the captaincy duties with Gregan named as deputy along with Stirling Mortlock, who starts the match on the bench.
Tuqiri will make his first appearance for the Wallabies this year in place of last week's debut hero Digby Ioane on the left wing.
Fiji-born dual international Tuqiri was put on a special training schedule when he arrived in the Wallabies camp last month to work on regaining his foot speed and, after sitting on the sidelines for the two-match series against Wales, is raring to go.
Drew Mitchell retains his place on the right wing, while inside him Adam Ashley-Cooper moves to outside centre, awarding Scott Staniforth his first Test cap on Australian soil at inside centre.
In the scrum, Adam Freier replaces Stephen Moore at hooker and forms an all-NSW front row with Matt Dunning and Al Baxter.
In the second row, 22-year-old Reds lock James Horwill makes his debut alongside Vickerman. Mark Chisholm goes to blindside flanker, where he started on three occasions for the Wallabies in 2006, while David Lyons has been awarded his first opportunity for the year at number eight.