Matildas stalwarts Ellie Carpenter and Emily van Egmond will miss the Olympic qualifier against Taiwan after returning to their clubs, while hamstrung winger Cortnee Vine is also sidelined.
Vine's absence for Wednesday night's game at Perth's HBF Park was expected.
The winger has returned to her club side Sydney FC for treatment after suffering a hamstring injury 10 minutes after entering the fray in Australia's 8-0 thumping of the Philippines on Sunday.
But Football Australia said deals had been in place for Carpenter and Van Egmond to return to their clubs before the third game.
Van Egmond is about to enter the US National Women's Soccer League playoffs with the Wave while Carpenter's Lyon return to action on November 6 against Paris FC in France's Division 1 Feminine.
The Matildas got maximum bang for their buck from Carpenter who played 90 minutes against Iran - scoring in the 2-0 win - and the Philippines, and was among Australia's best in both victories.
Van Egmond and Vine both played the full game against Iran and came on in the 65th minute against the Philippines.
Australia have effectively locked in top spot in Group A and a place in the third round of qualifying, when the four top-ranked sides will be whittled down to the two who will qualify for next year's Paris Olympics.
Heavyweights Japan and South Korea currently hold top spots in the two other groups, though specific dates and venues of the next qualifying phase have yet to be revealed.
"It is a bit of a weird situation because I suppose we could come up against someone like Japan and then one of us would be out," defender Steph Catley told reporters on Tuesday.
"But that is the nature of these types of situations ... the main thing we can do is just control what we can control.
'And for us, that is winning - and that is doing it however we need to and scoring as many goals as we can.
"So we will focus on the task at hand and make sure that we get ourselves in the best position possible."
"It's been nice to get off to a good start and get two wins.
"Now we have just got to make sure we're focusing and get this last win over and one with it."
Vittsjo defender Charli Grant is Carpenter's likely replacement at right-back in the starting line-up while Amy Sayer looms as Van Egmond's stand-in.
