Eighteen amphibian species once inhabited the sandstone gullies and ridges along the middle to lower reaches of Sydney Harbour. The amphibian fauna includes representatives from the two major Australian frog families. The major groups of Australian frogs are the Tree Frogs in the Family Hylidae (about 73 species Australia wide) and the Ground Frogs in the Family Myobatrachidae (about 112 species Australia wide).

Some species of frogs have integrated with urban development and can still be found in gardens and parklands in the harbour-side suburbs. Other species now only persist in the harbour region in small reserves or the larger, less intensively developed areas in the upper reaches of the northern tributaries.

All native frog species are protected within New South Wales and enquiries regarding the collection or disturbance of these animals should be directed the New South Wales National Parks and Wildlife Service.