Missing woman's body found in floodwaters

Police are yet to make a formal identification but believe the body to be that of 60-year-old Dianne Smith from the town of Eugowra, devastated by roof-high flash-flooding in the early hours of Monday.

Ms Smith last spoke to a relative by phone from her car that morning.

Ljubisa "Les" Vugec, 85, last seen at his Eugowra home around the same time, is still missing.

State Emergency Service chaplain Steve Hall said locals had been decimated by the disaster.

"Everything they hold dear has been swept away in a wall of water," he said.

Residents in nearby Forbes are meanwhile bracing for their second major flood episode in a fortnight.

The Bureau of Meteorology is warning the adjacent Lachlan River could meet the historic June 1952 peak of 10.8 metres on Thursday morning, while major inundation is expected to persist until the end of the week.

People in parts of the northwestern town of Gunnedah, where the Namoi River is on target to peak near 8.2m, and the central NSW community of Gooloogong have been told to evacuate.

In the 24 hours to Wednesday afternoon, the SES responded to 261 calls for help and performed 17 flood rescues.

Emergency Services Minister Steph Cooke said 122 warnings were active statewide and hundreds of homes had been destroyed.

Fourteen people were rescued in Forbes on Tuesday night after the Plainsman Motel was inundated, including an elderly couple and their daughter, rescued by a helicopter.

About 1000 people and up to 600 homes and businesses are affected by evacuation orders in the town.

Dorothy Woodcock has been helping move historical items, including artefacts from the bushranging era of Ben Hall, to higher ground at the local museum.

The Country Women's Association member said the group had been checking on people across town.

"I've never seen so much water," she told AAP on Wednesday.

"When the water goes down, people are going to need a lot of help, particularly farmers because they are the ones who are really affected."

Crews have been door-knocking and sandbagging after 120mm of rain fell in a matter of hours early on Monday, causing ferocious flash flooding and forcing Wyangala Dam to spill into the swollen Lachlan River.

The torrential rain doubled the height of Mandagery Creek at Eugowra on Monday, devastating the town of 800.

Initial assessments had found 216 of its roughly 300 homes damaged and 21 completely destroyed, the SES reported.

"Emergency services have engaged engineers to determine if houses are structurally sound and whether some residents may be able to return to those homes that are safe to enter," SES Assistant Commissioner Sean Kearns said.

"We expect the damage to be severe and widespread."

Residents have described two sudden and intense surges of water flowing through the town, washing away houses, knocking over structures and leaving destruction like a "war zone".

Kelly Chambers was celebrating her twin daughters' 23rd birthday on Sunday night in the house the family bought less than a year ago.

Hours later, they climbed out a window and waded through waist-deep water as a torrent tore through the village.

Ms Chambers, her husband, their three children and her parents eventually found a truck trailer to perch on for six hours before a fire truck delivered them to the evacuation centre at the showground.

"It's devastating. Anything that is a memory is gone," Ms Chambers told AAP.

Australian Associated Press