Penguin Island is a short distance of the coast at Rockingham, about 50km south of Perth. It's connected to the mainland by a shallow sandbar across which one can wade to visit the island and enjoy the aroma of penguin poop. The 2004 Boxing Day tsunami send a wave past the area; a number of people wading along the sandbar were washed off but were aided to shore by kayakers. By all reports it was a small wave, but carried a surprising amount of force.
It's entirely plausible in my opinion that should a similar event occur in a slightly different way the west coast could be in a world of trouble. So could the rest of Australia's coastline, depending on the epicentre at the time.
Just as someone in an Australian forest must consider bushfires as a risk, those near the coast must realise that water damage is a risk. It's one of the negatives of living on an island.