Emergency crews were busy in NSW after severe thunderstorms hit large areas of the state, including densely-populated parts of Sydney and the Illawarra.
Fifty crews worked through the night in Appin, a small town south of Sydney, after the storms brought down trees and blocked the main access road in both directions.
Access was restored about 2am.
There were also 48 incidents in the central west of NSW, including the downing of several large trees in Wellington, where roads were closed and properties damaged.
Wild storms brought down trees at Appin, south of Sydney. (Supplied/AAP PHOTOS)
In Queensland, flash-flooding hit the isolated mining town of Mt Isa after severe thunderstorms and heavy rainfall, with all but two of the local bridges inundated.
Water rescue teams were required to help three vehicles out of floodwaters.
Moderate or minor flood warnings were in place for several rivers in NSW and Queensland, while flood-watch warnings were issued for NSW's central west and south-west catchments.
Bureau of Meteorology senior meteorologist Miriam Bradbury predicted severe thunderstorms and heavy rain across much of NSW and the ACT on Friday.
"A cloud band will extend across eastern Australia, bringing humid conditions and scattered showers and thunderstorms," she said.
"Severe storms are possible across Sydney once again on Friday, with the risk of flash flooding, where storms bring heavy falls."
In Queensland, the BOM forecast severe thunderstorms were likely in in-land areas.