Thousands of people have already been forced to evacuate in northern NSW ahead of the cyclone's predicted arrival on Saturday.
Many residents across a stretch of coastline and hinterland spanning more than 100km from Evans Head to the Queensland border were also without power and facing the prospect of days-long outages on Friday morning.
In Lismore, where several people died and more than 1000 homes were badly damaged during the 2022 floods, locals were told to evacuate by Thursday night from low-lying areas.
The local river reached minor flood level and could be hit by major flooding within a day after 300mm of rain fell in some areas in a 24-hour period.
Several other rivers across northern NSW were at minor or moderate flood levels as the region readied for the state's first cyclone in 35 years.
Alfred is expected to cross the coast north of Brisbane, however a cyclone warning is in place for an area from north of Queensland's Sunshine Coast to near Grafton in northern NSW.
Deputy Premier Prue Car said there had already been significant flooding in the region and there was high potential for further flooding.
"We know that there is a significant amount of anxiety in the community as we wait for this," she said.
More than 300 schools have been closed statewide and are due to remain shut on Monday.
Over 43,000 homes and businesses in northern NSW are without electricity as heavy wind brought down power lines overnight and in the morning.
Local provider Essential Energy warned it could take several days to restore power due to the "extreme conditions", the damage to infrastructure and the ongoing storms stopping crews from doing their work.
The number of outages is expected to grow in the coming days as winds pick up further and more power poles are felled.
The NSW State Emergency Service received more than 1000 calls for help within 24 hours and performed a handful of rescues due to flash flooding.
More than 100 defence personnel had been deployed to the region in anticipation of another natural disaster, while 23 emergency warnings were in place and 17 evacuation centres operating.
North Coast Minister Rose Jackson said the local community had "endured a hell of a time" over the past few years and were now facing another potential disaster.
Many residents are still living in temporary housing after the previous floods, while  others have moved into homes that were badly damaged due to the lack of affordable options.
"I think the community of the Northern Rivers is a really wonderful, strong, resilient community, but understandably this is a really difficult time for them," Ms Jackson said.
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