Gary Speed's team will play the Socceroos at Cardiff City Stadium on Wednesday 10 August, as the coach looks to follow up his first win in charge against Northern Ireland.
Montenegro will visit Cardiff City Stadium on 2 September, while Switzerland will be Wales' opponents at Swansea's Liberty Stadium on 7 October.
An FAW statement read: "The Football Association of Wales can confirm that Wales will play a friendly international against Australia on Wednesday 10 August. The venue will be the Cardiff City Stadium and kick-off will be at 7.45pm.
"This will be the first of two international fixtures at the stadium in the space of three weeks, with Wales set to face Montenegro in Cardiff on Friday 2 September.
"The FAW can also confirm that the final home fixture in the qualifying campaign against Switzerland will be at the Liberty Stadium in Swansea on Friday 7 October."
Wales also have to travel to face England and Bulgaria in Group G but their hopes of qualifying for the finals in Poland and Ukraine were hampered after they lost their first four matches.