"It is always a challenging task to reduce a squad, however this is the nature of professional sport at the highest level," said van Marwijk.
"Overall, I believe we have named a strong and ambitious squad for our training camp in Turkey and friendly against the Czech Republic in Austria."
The Socceroos link-up for their training camp in Antalya on Sunday ahead of the clash with the Czech Republic in St Polten on June 1.
"I am sure that in training in Antalya, and in our match against the Czech Republic, we will see players pushing to go to a higher level as they compete for a place in the final squad," added Dutchman van Marwijk.
Maclaren's omission was the most controversial, having scored a hat-trick at the weekend for Hibs in their 5-5 draw with Rangers.
The 19-year-old is also eligible to play for Iran, but appears to be locking in his international future with Australia.
One other uncapped player, defender Fran Karacic, also remains in contention.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)