Emergency services rushed to the scene of a crash involving two army trucks at Tregeagle, nine kilometres south of Lismore, on Saturday evening.
More than 20 ambulance resources were deployed to help 36 patients.
A number of patients have been taken to Tweed and Lismore Hospitals but NSW Ambulance told AAP not all 36 required transport.
Meanwhile, authorities have also located the body believed to be a 61-year-old man who had been swept away in floodwaters after clinging to a tree for help.
A search had been launched after the man's ute was swept into floodwaters at Megan, about 25 km north of Dorrigo.
He was able to get out of the ute and climb into a tree about 30 metres from the riverbank but was swept away before emergency personnel could reach him.
After extensive search efforts spanning more than 24 hours, his body was found on Saturday afternoon.
In southeast Queensland, residents are still being battered by destructive winds after ex-tropical cyclone Alfred was downgraded, with gusts more than 90km/h recorded on the Gold Coast on Saturday afternoon.
Authorities urged residents not to become complacent as the tropical low became unpredictable and might still bring more dangerous conditions.
Up to 500mm of rain could fall as the remnants of the storm move inland, reaching Dalby by midnight on Saturday and Goondiwindi on Sunday.
The massive rain band stretching across southeast Queensland might lead to life-threatening flooding in coming days, Bureau of Meteorology's Matt Collopy warned.
More than 200,000 people across the southeast and northern NSW remained without power on Saturday afternoon, the biggest loss of power in Queensland's history.
Energex crews were working tirelessly to reconnect homes but it remained a particular challenge on the Gold Coast with the strong winds.
Emergency warnings were cancelled in Queensland but thousands of residents in NSW remained in limbo after evacuating over flood risks.
There has been no loss of life in Queensland but one family was lucky to have escaped injury after four people were rushed to hospital on the Gold Coast due to carbon monoxide poisoning.Â
Gold Coast Acting Mayor Donna Gates said it appeared the family had been running a generator inside, sparking a warning for others to keep the devices outside.
Residents in northern NSW's Tweed Shire Council and Bilambil Heights were told to conserve their drinking water and boil any from taps as power outages impact reservoirs.
About 180 Australian Defence Force personnel were on the ground in both states with more on standby.
Shops began to reopen on Saturday across Queensland while Brisbane and Gold Coast airports were looking to reopen on Sunday if safe to do so.
Supermarkets were reopening on a case-by-case basis in Queensland and some public transport would resume on Sunday excluding trains across the southeast and buses on the Gold Coast.
Some Queenslanders also were getting back to normal with thrillseeker Chris Haughton having little fear of the gusty conditions as he ran out into the water at Brighton, east of Brisbane, to kite surf.
The local said Saturday's conditions were prime for a day on the water after Alfred crossed Moreton Island as a category one then diminished to a tropical low, lingering off the coast.
But he had hoped Alfred would pack more of a punch.
"A bit of a fizzler," he told AAP.
"I'm a little disappointed ... I'm selfish because I want really strong wind to kite."
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