The AusSeabed Marine Data Portal contains a variety of compilation (I.e. the most recent 50 m grid of the Australian seafloor, the 30 m Northern Australia grid, the 30 m Great Barrier Reef grid, and the 5 m NESP grid) and survey-based (I.e. the recently completed Visioning the Coral Sea Falkor survey) bathymetry datasets.
For more information please visit http://www.ausseabed.gov.au/data