Dangerous rainfall has again forced families out of their homes as major river rises swamp coastal areas and heavy rainfall causes flooding in NSW's far west.
In flood-hit Lismore, the Wilsons River rose several metres on Tuesday and is expected to reach a major flood level.
The Bureau of Meteorology (BOM) warns the river could reach 10.6 metres.
People have been told to leave central Lismore by 4pm on Tuesday, with floodwaters expected to again flow over the town's levee.
Flood Recovery Minister Steph Cooke said the people of Lismore must heed the warnings.
"This latest event on top of the one we experienced a month ago, that unprecedented natural disaster, that saw flooding over two metres beyond the previously set record rush through your communities - this is the last thing you want at this time."
Flood recovery centres opened after the February floods had been closed for the next 48 hours and the SES had positioned resources, including aircraft, in the region in anticipation of flooding, Ms Cooke told parliament on Tuesday.
About 4,000 defence and 1,000 emergency services personnel remain in the region.
Lismore mayor Steve Krieg said on Tuesday morning residents were suffering from flood fatigue.
Rainfall totals of close to 150mm in six hours have led to flooding in the Northern Rivers region, with throughout Lismore on Tuesday, the BOM said.
Further inland, major flooding is occurring at Angledool as floodwaters from Queensland caused the level to rise on the Narran River.
Further flash flooding, which could become life-threatening, is predicted for the Northern Rivers, the Mid North Coast and Northern Tablelands on Tuesday night.
Rainfall could intensify to six-hourly totals of between 200mm and 300mm, with Lismore, Grafton, Coffs Harbour, Port Macquarie, Tenterfield and Dorrigo among the affected areas.
Seven evacuation orders were issued overnight, including for Tumbulgum and surrounds in the Tweed Shire, low-lying parts of Billinudgel, Mullumbimby and Kyogle in the Northern Rivers, North Lismore and areas of South Lismore, East Lismore, Lismore CBD Basin, and Girards Hill.
Hazardous surf will pummel the Byron Coast on Tuesday, with rough seas to extend to Coffs Harbour and the Macquarie and Hunter Coast on Wednesday.
The thunderstorms are caused by a low-pressure system sitting off the NSW coast will bring showers in the coming days all the way south to Sydney, the BOM's Jonathan How said.
As the system moves south it will become windy across the state's eastern coastline, becoming strongest on Friday with the potential to bring down trees and power lines, he said.
"Thankfully though, this rain event won't be quite as long-lasting as the previous rain event so we will see conditions really ease towards the latter part of the week," Mr How said.
Man missing, Queensland town on flood alert
A man is still missing in floodwaters in southern Queensland, with a major flood underway in the town of Dalby and large parts of the Gold Coast on flood watch.
The man in his 40s was swept away after getting out of his car when it became stuck in a torrent at North Branch, south of Toowoomba, about 6am on Monday.
Queensland Fire and Emergency Services (QFES) Chief Superintendent Brad Commens says police are still searching for the man on Tuesday.
"That's a tragic situation," he told ABC radio on Tuesday.
"We don't have any further update from the Queensland Police at the moment."
A major flood is occurring Dalby, west of Toowoomba, on Tuesday after the swollen Myall Creek broke its banks.
The BOM said floods peaked at 3.6 metres, below the record 2011 peak of 3.74m, in the early hours of the morning.
Western Downs Mayor Paul McVeigh said 15 people stayed in the local evacuation centre, but it was too early to assess how many homes had had water above the floorboards.
He said it looked as if most of Dalby had "dodged a bit of a bullet" as floodwaters subsided on Tuesday.
Western Downs Regional Council Mayor Paul McVeigh. Source: AAP / Dan Peled
Chief Supt Commens said QFES had made 14 swiftwater rescues and responded to 240 calls for help since a massive low pressure trough crossed the state's southeast coast on Monday.
The system dumped almost 300mm of rain on multiple parts of the Gold Coast in the 24 hours to 5am on Tuesday, the Bureau of Meteorology said.
Almost 150mm fell in six hours at Coplicks Bridge, triggering emergency flash flood alerts for parts of Tallebudgera overnight, but they've since been cancelled.
The BoM said 80-140mm of rain, and up to 180mm, could fall in parts of the Gold Coast, Beaudesert, Coolangatta, Boonah, Mount Tamborine and Springbrook before the system moves into northern NSW later on Tuesday.
Gold Coast Acting Mayor Donna Gates said sandbag stations would remain open for residents on Tuesday.
"If you had some flooding last time just be prepared because there could be up to 140 millimetres of rain today," she told AAP in a statement.
"And after that it will clear we're through the worst of it. So just take care and be aware of your circumstances."
Three schools at Tallebudgera and one at Warra, on the Darling Downs, were closed on Tuesday.
The deluge has also caused more than 170 road closures across southern and southeast Queensland, the Department of Transport and Main Roads said.
Chief Supt Commens urged drivers to be extremely careful while out and about.
"Don't drive in the floodwaters, don't let your kids play in floodwaters or drains. It's just not safe," he said.
