The All Blacks have dropped back Rene Ranger and forward Liam Messam from their squad to face the Wallabies in two weeks time.
"I think we are probably playing at 75 percent, so I think we can get a lot better," Henry told The Dominion Post after the All Blacks have picked up maximum points from their first two matches.
"It's gone better than planned ... if you'd said two weeks ago we'd have 10 points out of South Africa I would have laughed at you.
"[But] We've prepared well ... we had a good [June] series and we've had a good start to the Tri-Nations. The guys prepared individually well and we are just a step ahead at this point in time."
Henry also issued a warning to the Wallabies saying that his side can only get better after they have beaten South Africa twice.
The All Blacks coach has dropped Rene Ranger for Joe Rokocoko and Liam Messam Victor Vito who return from injury for the Test on July the 31st in Melbourne.
Prop John Afoa who can also cover at hooker, as well as lock Anthony Boric have been included in the squad traveling to Melbourne even though they were not required for the South African Tests.
Halfback Alby Mathewson will also join the squad as cover for Piri Weepu who kicked a penalty in Saturday game as he is expecting his first child.
Australia have not kicked a ball in the TriNations but are placed second. They play the Springboks this weekend and are expected to play a similar style to the All Blacks using pace and spreading the ball wide.
Henry has made a number of All Blacks available for the pre-season ITM Cup provincial rugby games if they are required this weekend in order to keep them match fit.
On Wednesday, Auckland plays Northland in Dargaville, North Harbour takes on Counties-Manukau in Pukekohe, while Waikato will play Japanese side Toshiba in Hamilton.
On Friday Wellington heads south to take on Canterbury in Christchurch, while in Palmerston North, Manawatu hosts Hawke's Bay.
The players available for ITM Cup pre-season matches are John Afoa (Auckland), Anthony Boric (North Harbour), Aaron Cruden (Manawatu), Israel Dagg (Hawke's Bay), Corey Flynn (Canterbury), Liam Messam (Waikato), Rene Ranger (Northland), Benson Stanley (Auckland) and Victor Vito (Wellington).
All Black squad to play Wallabies
Forwards: John Afoa, Anthony Boric, Tom Donnelly, Corey Flynn, Ben Franks, Owen Franks, Jerome Kaino, Richie McCaw, Keven Mealamu, Kieran Read, Brad Thorn, Victor Vito, Samuel Whitelock and Tony Woodcock.
Backs: Daniel Carter, Jimmy Cowan, Aaron Cruden, Israel Dagg, Cory Jane, Mils Muliaina, Ma’a Nonu, Josevata Rokocoko, Conrad Smith, Benson Stanley and Piri Weepu.
