Australia is a member of the Asian Football Confederation but not an asian country therefore they do no count for this question. Only Iran (20), Japan (24), Qatar (50), Saudi Arabia (51), South Korea (28) count.
The Asian countries in the tournament (with their FIFA World ranking before the tournament in brackets after them) are: Iran (20), Japan (24), Qatar (50) (hosts), Saudi Arabia (51), :South Korea (28). Australia (38) are part of the Asian football confederation but I presume they're not being counted here?
(from here: https://en.wikipedia.org/wiki/2022_FIFA_World_Cup#Qualification)
Australia does not count. I edited the description.