Results from Part 2 of the South East Australia Linkage teleseismic experiment are presented for the first time, and enhance understanding of deep Earth structure beneath southwestern New South Wales. A total of 187 distant earthquakes recorded by 31 short-period seismometer stations were used to constrain three-dimensional variations in P-wavespeed in the upper mantle using teleseismic tomography. The new data were also combined with pre-existing data from adjacent arrays to build a high-resolution model of the upper mantle in southeastern Australia. The resulting images reveal that the upper mantle consists of several distinct domains of fast and slow P-wavespeed that provide unprecedented insight into compositional and temperature variations related to lithosphere of different origin, and more recent processes such as Cenozoic volcanism. One of the main results from this study is the presence of a pronounced west to east transition from higher to lower Vp near the eastern edge of the Stawell Zone. One possible explanation for this feature is that Precambrian continental lithosphere extends beneath the western subprovince of the Lachlan Orogen, which has important implications for the tectonic evolution of the Tasmanides, and the location of the boundary between the Lachlan and Delamerian orogens. However, the absence of good constraint on crustal structure, and possible overprinting of Palaeozoic velocity anomalies by such recent events as magmatic underplating which accompanied rifting and subsequent opening of the Bass and Otway basins and the Tasman Sea, means that further data are required. Future work in southeastern Australia will use receiver functions and ambient noise data that have the potential to resolve structures within the crust at high resolution, and naturally complement the teleseismic data, which only constrain the upper mantle.