A man is missing after his 4WD was washed off a bridge by fast-moving floodwaters northeast of Dorrigo in northern NSW on Friday.
He left the car and secured himself to a tree but was swept away about 3pm, NSW Police said in a statement, as a search continues.
Tropical Cyclone Alfred is expected to hit on Saturday, but many communities are already facing heavy rain and the prospect of days-long power outages.
In Lismore, where several people died and more than 1000 homes were badly damaged during the 2022 floods, locals have been told to evacuate low-lying areas.
Major flooding is expected with the threat of intense and prolonged rain driving rapid and dangerous river rises during the state's first cyclone in 35 years.
About 19,000 people have been urged to evacuate.
Resilient Lismore director Elly Bird told AAP many did not wait to be told.
"Our community has been preparing for almost a week now, and many people were fully evacuated before that order was made," she said.
"It's only the thinnest of silver linings from 2022, (but) we know really clearly how quickly things can change."
The organisation has been relocating in preparation to assist residents and businesses access support and clean-up in the likely event floodwaters go over the town's levee again.
"There's a lot of anxiety in the community, and uncertainty, because we just don't know how high the river might go," Ms Bird said.
Resident Ruth Gallagher told AAP Lismore's town centre was quiet after locals and businesses had heeded the warnings.
"People have done all that they can do in preparation ... you just have to wait and see what happens," she said.
NSW Premier Chris Minns encouraged those evacuating to seek shelter with friends or family.
"There are emergency evacuation centres that are located if there are no alternatives," he said.
"These are more of a life-raft, rather than a cruise ship."
Greens MP Sue Higginson told AAP evacuation centres should have been set up earlier as the region finds itself back in the path of an extreme weather event.
"We need purpose-fitted, ready evacuation centres in the northern rivers ... the evacuation centres have been absolutely struggling," Ms Higginson said.
More than 300 schools have been closed statewide and are due to remain shut on Monday.
Communities face days without electricity as the cyclone damages network infrastructure.
Energy Minister Penny Sharpe said about 38,000 homes were without power, mainly between Tweed Heads and Yamba on the state's far north coast.
"Households and businesses need to prepare for the real possibility that they will be without power for an extended period of time.
"Dangerous conditions will likely prevent crews accessing and repairing damage to the network," she said.
