A mother and her two children are feared dead as police work to recover a car that was swept into a flooded northern NSW river.

Police say an operation is under way to recover the vehicle, which went into the Tweed River off Dulguigan Road in Tumbulgum at 1.40pm on Monday.

It’s not yet known if the occupants — believed to be a female driver and her two children — are alive but the car is understood to be fully submerged, a NSW Police spokeswoman told AAP.

A nine-year-old girl was able to escape the car as it was dragged into the water and residents at a nearby house came to her aid.

Witness Thomas Grinham saw the girl reporting her family members were swept by floodwaters.

“She was screaming (that) her mum, little sister and older brother had gone into the river in the car,” he told the Seven Network on Monday.

Another young witness, Sophie Grinham, said she saw the girl’s father respond to the pleas.

“The husband came down, and dad and two other boys just jumped into the water and couldn’t dive deep enough,” she told Seven.

The child was taken to Tweed Heads Hospital for bruises and cuts and was being cared for by family members.

Authorities using boat equipped with sonar equipment found the missing car five metres from the river bank around 3.25pm on Monday.

Deluge of rubbish

Lismore residents, meanwhile, have returned to a deluge of rubbish and muck as the clean-up begins in earnest throughout the flood-stricken northern NSW town.

Lismore Mayor Isaac Smith said about 3000 homes and businesses in the town centre were damaged by floodwaters, which reached near-record levels.

“It’s pretty devastating to see piles of rubbish above your head and 10 to 20 metres wide. It’s heartbreaking,” Mr Smith told AAP on Monday.

Mountains of rubbish await flood-affected residents. Photo: Channel Nine

The Rural Fire Service has set up a tent city for hundreds of workers, including nearly 400 SES volunteers.

Food trucks and petrol tankers have started bringing in supplies after the roads were cut for days.

For the first time in 12 years, the heavy rain from ex-tropical Cyclone Debbie caused the town’s levee to break its bank.

Snakes also posing problem

Residents forced to flee their homes in the face of the NSW and Queensland floodwaters have also been warned about snakes taking up residence in their homes in their absence.

While evacuation orders are still in place in some parts of northern NSW, Lismore residents have been given the all-clear to return home after the town’s massive flood.

A 3m python found on the Gold Coast. Picture: Tony Harrison

Along with the confronting sight of mounds of destroyed belongings, mud and rubbish, evacuees are warned of the dangers of unwanted wildlife seeking refuge from the flooding.

“We had people finding snakes, spiders and rats,” SES spokesman Phil Campbell told AAP after a significant increase in snake sightings on the Gold Coast as floodwaters subside.

Queensland snake catcher Tony Harrison told The Gold Coast Bulletin he had been “flat out” catching exhausted reptiles who had been attempting to escape the floods.

“They’re in lots of weird places, normally certain species don’t climb but people have been cleaning up in the shed … and found brown [snakes] in the rafters.”

Mr Harrison said he had caught and relocated at least 20 snakes since the wet weather began and had found snakes in cars, on people’s verandas and in chicken coops.

One python caught in the Gold Coast hinterland suburb of Clagiraba measured more than three metres long – one of the biggest Mr Harrison said he had seen in 25 years.

Dramatic rescue

A family was saved from the roof of their home on the northern Gold Coast minutes before it was swept away in floodwaters.

The rescue played out in the early hours of Saturday morning as the flooded Albert River devastated a street at Luscombe, the ABC reported.

The mother and two children waited on the roof for hours in the dark and were helped into a boat, along with another man and two dogs who were inside the home.

Fifteen minutes later, the house was swept away.

“It took us approximately an hour to dodge the high trees, the powerlines, the stuff that was coming down the river,” disaster management officer Jim Ferguson told the ABC.

“I climbed over the balcony hands and knees along the awning, stood up and made my first real contact with the parent and the two kids.

“It was tough … the scariest thing I’ve ever done.”

Watch the footage of the house being swept away

Rockhampton flood downgraded but still ‘significant’

Rockhampton residents have received some good news, with authorities now saying the expected flood will not be as bad as previously thought.

But Queensland Premier Annastacia Palaszczuk has warned locals they “are not out of the woods yet”.

The Bureau of Meteorology said on Monday morning the latest forecast was for a flood peak of nine metres on Wednesday, just under the 2011 flood level.

Authorities had warned over the weekend that the Fitzroy River could peak at 9.4 metres on Wednesday or Thursday, making it the worst flood in more than 60 years.

At that level, Rockhampton Regional Council warned 5400 properties would be under threat, including 3000 homes.

But a major flood warning still exists for the Fitzroy, with extra emergency crews sent to the town for flood preparations.

“Nine metres is still a significant event,” Ms Palaszczuk said on Monday.

– With AAP & ABC