In some Chlorophyllum species the ring is loose and can break or erode with age and yours is clearly a well-weathered specimen. When you refer to poisonous Chlorophyllum, you probably have Chloropyllum molybdites in mind. This gives a dull or dirty greenish spore print (quite striking despite the dowdy colour) and the gills take on the same colour. That species has been reported from some warmer parts of Australia, but not from the local area. On the general subject of toxicity of Australian fungi, most fall into the category 'not known', since there has been neither a great deal of detailed chemical analysis nor a long period of discovery by trial and error, especially error!