Thats what is called a release call. Both genders do it in a lot of species. It is used by females to let certain males that their attention is unwanted and by males to let other males know they have made a bad choice in a mate. "Get off me dude!"

By no means is this a call or "croak". There are some species in which both genders call, Xenopus laevis comes to mind, but Litoria caerulea is not one of them.