Tens of thousands of Australians remained isolated and thousands were without power on Saturday, authorities said as conditions in New South Wales eased after days of heavy rain that caused widespread flooding.

Floodwaters were slowly subsiding but more than 20 emergency warnings remained in place, with the focus shifting to assessing properties and delivering supplies to cut-off communities.

NSW emergency authorities estimated up to 10,000 properties had been damaged by flooding, mostly in central and northern parts of the state.