Heavy rain, thunderstorms and large hail forecast for northern NSW and Queensland have emergency crews on stand-by on New Year's Eve.
A wild weather system was stretching more than 1000km from Port Macquarie to Rockhampton on Sunday afternoon, with parts of Queensland's Central Highlands and Coalfields, Maranoa and Darling Downs regions the most severely affected.
Slow-moving thunderstorms hung around the coast with heavy rainfall in excess of 70mm falling in the space of an hour in Coffs Harbour and dangerous flash flooding at Sawtell.
Weather bureau senior meteorologist Jonathan How urged residents to stay on top of flood warnings.
"Areas of heavy rain with thunderstorms could produce flash flooding as well as rapid rises in creeks, rivers and storm drains," he said.
The outback mining town of Dysart received a deluge of 62 mm in the 30 minutes to 5.30pm.
Severe thunderstorms continue to batter inland areas of northern, central and southern Queensland.
Meanwhile, a severe thunderstorm warning for damaging winds was in place over the Gregory district in the Northern Territory.
A group of thunderstorms was threatening Timber Creek and Yarralin with 90 km/h wind gusts recorded at Delamere Weapons Range.
Strong wind warnings have been issued for the Byron Coast in NSW and several coastal areas in Western Australia including eastern and western Pilbra, Perth, Bunbury, Leeuwin, Esperance and Eucla.
By 8pm a severe thunderstorm warning was cancelled, though heavy rainfall is forecast to continue in the northeast.
On Saturday, wind gusts reached 93km/h at Gympie, while 64mm of rain fell at Cedar Pocket Dam in Queensland.
The Sunshine Coast was also hammered by rain, with Beerburrum recording 110mm in two hours and Landsborough 67mm in 30 minutes.
Crews confirmed four houses in the state's southeast were "completely destroyed" and 750 homes had suffered minor to severe damage in storms since Christmas, Deputy Premier Cameron Dick told reporters in Jimboomba on Sunday.
He said there had been 3000 calls to the State Emergency Service since late Christmas Day and about 18,000 people around the state were still waiting for power to be reconnected.
"We've got crews out cleaning the streets trying to get that debris cleared so we can get the power crews in," Mr Dick said.
Up to 70 defence force veterans and retired emergency service personnel are assisting the storm cleanup in southeast Queensland.
They have been deployed to the worst affected areas including northern Gold Coast, Tamborine Mountain and Jimboomba to remove fallen trees, clear debris, stabilise buildings and improve access to homes.
Severe weather between Christmas Eve and Boxing Day resulted in 10 deaths in Queensland and Victoria, among them a nine-year-old girl lost in a stormwater drain.
NSW SES crews were kept busy, responding to 473 calls for help and conducting six flood rescues across the Christmas weekend.