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This subspecies occurs within Australia in the states of Victoria, eastern Queensland (including Cape York), New South Wales and south-eastern South Australia. It is a vagrant or accidental visitor to the Australian Capital Territory. It is also the subspecies believed to occur within New Guinea.[

Pomoatostomus temporalis rubeculus – This subspecies occurs in Australia within the states of Western Australia, Northern Territory, western Queensland and a small area of northern South Australia.

The breast colour is usually used as the distinguishing morphological character between the subspecies, with a creamy white breast grading to mid-grey in P. t. temporalis and a mid to deep Rufus brown breast in P. t. rubeculus. Other differences relate to brow coloration, facial bands through the eye, tail length and overall size.[  A zone of intergradations occurs between the two subspecies in north-central Queensland.

 

The key process that has led to the decline of the eastern subspecies of the grey-crowned babbler has been the historic loss and fragmentation of its preferred woodland habitat.[  Grey-crowned babblers generally have a poor ability to immigrate across unsuitable habitats. As a consequence of fragmentation, breeding success and groups sizes decline. Babbler groups are more susceptible to stochastic events leading to local extinction from a fragment. Once a fragment has lost its population of grey-crowned babblers, natural re-colonisation rarely occurs because of its poor dispersal ability.