Residents have been stranded on the roofs of their homes in the NSW Mid North Coast, after more than 500 millimetres of rain fell in some areas.
The State Emergency Service was inundated with calls about 2:00am, predominantly from Corindi, 36 kilometres north of Coffs Harbour.
"The amount of rainfall just hasn't been able to get away and that entire Corindi floodplain area has come up rapidly and caught a lot of people unawares at that hour of the morning," said SES Coffs Harbour deputy unit commander Martin Wells.
Mr Wells said in one street, there had been eight calls for help.
The Westpac Rescue helicopter assisted the SES, which conducted about 15 flood rescues.
Mr Wells said the most disappointing part of the SES's work overnight was responding to three vehicles that had driven into floodwaters.
Homes inundated, berry crops lost
Upper Corindi resident Jayde Mckenzie said her home was completely inundated by floodwaters with her four children in the house.
"I woke up at 2:00am and by 2.45am, it was all through the house. It was just like a rising current," Ms Mckenzie said.
"We had to get as much stuff as we could and stood on the kitchen bench. We didn't have time to get out of the house," she said.
The Corindi area is a blueberry and raspberry growing region, and farms are counting the cost of the damage.
Greenhouses have been destroyed in some areas.
Goods train derailed
The flooding is also hampering the salvage operation of a freight train that has derailed in nearby Nana Glen.
The freight train derailed near Morrows Road.
The Environment Protection Authority (EPA) is working with farmers to prevent any spread of leaked diesel from the derailed freight train.
Superintendent Rod Chetwynd said 14 carriages came off the track in the flooded paddocks of a farm and one of the train's three locomotives was lying on its side.
"Up to 8,000L, we've already confirmed, has leaked into the area up there."
Salvage operation 'treacherous'
Superintendent Chetwynd said booms were being used to prevent any fuel from spreading.
"Our operations officer … is working with the EPA and they're … booming those waterways with hydrocarbon booms to stop any spread of diesel, even just as a precaution," he said.
Superintendent Chetwynd said the salvage operation was completely dependent on the rainfall and how quickly the area dried out.
"There were reports of [up to] 500mm of rain in those mountainous areas overnight — really heavy, fast rainfall," he said.
"The ground's already sodden up here from rainfall that we've received over the last 3 months.
"To access that area with heavy equipment is going to be really treacherous, obviously, with bogging and those sorts of things — if we can get in there at all."
