Molong floods rip through 'like a cyclone'

"It looks like a cyclone has been here. It's a disaster zone," Ms Porter told AAP on Monday morning.

As heavy and unrelenting rain fell on Sunday night, NSW Fire and Rescue crews made a makeshift landing strip using flashing lights on the school oval to guide a Defence Force helicopter tasked with rooftop rescues.

Firefighters and police rescued several people, having to wade through chest-deep water to get to one woman stranded in her home.

Ms Porter said the water was up to her armpits as she checked on her mother at the family's motel about 2am.

"I was swimming. It was up to the gazebo," she said.

"I couldn't even get across the yard because it was flowing too fast.

"Now it's just a muddy mess, and we've got more rain coming."

The immense depth and force of the water carried at least two shipping containers down the main street, lifted parked cars, knocked out the back wall of the supermarket and wiped out several small businesses.

Real estate agent Scott Petersen said the town centre looked "apocalyptic" on Monday morning.

"There were cars pushed away, every shop has had five-foot of water through it," Mr Petersen said.

"It happened so quickly, it busted all the glass out and it was an absolute disaster.

Mr Petersen said his McGrath office had been flooded three times in less than 12 months.

"It's starting to wear a little bit thin."

Molong, 35 kilometres northwest of Orange, attracted tree changers in recent years and several new businesses moved into its heritage main street buildings.

"It has just started to get its own identity, real estate is ever-increasing," Mr Petersen said.

"This is a real kick in the guts for everyone."

Wendy Henry, who owns the Booful homewares shop, lost much of her stock.

Ms Henry said the Molong creek was fast-flowing - but not full - on Sunday afternoon, and she sandbagged her shop at night.

"We had a huge cloud burst and so much rain fell," she said.

"The force of it has been unbelievable. It smashed everything inside to pieces."

She said wooden pallets were swept from the highway down the main street, busting through the windows of about five shops.

"It's just heartbreaking."

"I didn't expect this kind of devastation."

Many residents came dressed in the gumboots and gloves to help clean up, while locals used their trucks and bobcats to clear debris and rubbish.

"We are so lucky we're in a small country town that's very community-minded," Ms Henry said.

"It was an eye-opener. You think a sandbag will keep the water out a bit, but we didn't count on the force of this."

Australian Associated Press