We describe predictions of post-glacial relative sea level (RSL) variations in Australia and New Zealand that incorporate a realistic evolution of the ocean-continent margin and compare these to predictions which assume that the ocean-continent interface is fixed to the present-day coastline geometry. We find that the predicted amplitude of Holocene sea level highstands in this region can be increased by more than 2 m when a time-dependent ocean-continent margin is incorporated into the modeling procedure. Future attempts to refine both mantle viscosity and Late Holocene melting events based on the prediction of a set of these highstands should adopt a theory that includes this extension. ¿ 1998 American Geophysical Union