Full genome sequencing of 11 Australian and one New Zealand subtype H7 avian influenza A isolates has enabled the comparison of sequences from each of the genome segments to other sequenced subtype H7 avian influenza A. The inference of phylogenetic relationships for each segment has been used to develop a model of the natural history of these viruses in Australia. The Australian H7 hemagglutinins form a monophyletic clade, consistent with the long-term, independent evolution due to geographic isolation. Based on the analysis of the other available H7 hemagglutinins sequences, the three other geographic regions for which similar monophyletic clades have been observed were confirmed; these regions are Eurasia (Africa, Europe and Asia), North America and South America. Analysis of datasets of H7N1, H7N3, H7N7 neuraminidase sequences revealed congruent relationships indicating a similar pattern of geographically constrained independent evolution for each of the neuraminidase subtype datasets. This pattern of evolution in geographic isolation is supported by analysis of each of the six remaining segments of the Australian isolates. These data in combination with the occurrence of five different combinations of neuraminidase subtypes (H7N2, H7N3, H7N4, H7N6, H7N7) among the 11 Australian isolates suggests a single maintenance network of hosts, probably comprising several avian species, for subtype H7 avian influenza A in Australia. A clear time based evolution of the hemagglutinins sequences despite the occurrence of multiple neuraminidase types suggest a genetic pool from which a variety of reassorants arise rather than the presence of a small number of stable viral clones. This pattern of evolution is likely to occur in each of the regions mentioned above as well as possibly a new region comprising of New Zealand, based on the apparent genetic isolation of the isolate analyzed in this study.