There is considerable archaeological discussion as to the route taken by the first colonisers . People appear to have arrived by sea during a period of glaciation , when New Guinea and Tasmania were joined to the continent . The journey still required sea travel however , making them amongst the world 's earlier mariners . Scott Cane wrote in 2013 that the first wave may have been prompted by the eruption of Lake Toba . If they arrived around 70,000 years ago , they could have crossed the water from Timor , when the sea level was low ; but if they came later , around 50,000 years ago , a more likely route would be through the Moluccas to New Guinea . Given that the likely landfall regions have been under around 50 metres of water for the last 15,000 years , it is unlikely that the timing will ever be established with certainty
eruption of Lake Toba
Toba catastrophe theory
History of Australia