On the 64th day of the state’s flood crisis, emergency services are stretched to the limit dealing with one of the biggest operations in the state’s history.

More than 160 emergency personnel, including 12 volunteers from New Zealand, have been deployed to help in the flood-ravaged central-west and more are expected from Singapore and the US.

Fourteen people have been rescued from a pub roof in Forbes overnight, as the town braces for its highest flood level in 70 years.

With the flood peak yet to arrive, Forbes Mayor Phyllis Miller estimated two-thirds of the town was already inundated.

The Bureau of Meteorology has forecast levels similar to flooding at Forbes in 1952, with the Lachlan River expected to peak at 10.8 metres later today.

The body of a woman missing in the floodwaters has been found.

Police are yet to make a formal identification but believe it may be that of Diane Smith from the central western town of Eugowra, devastated by roof-high flash-flooding in the early hours of Monday.

Smith, 60, 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 Eugowra has been decimated in the disaster.

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

The Bureau of Meteorology is warning the Lachlan River at Forbes could meet the historic June 1952 peak of 10.8 metres by Wednesday morning, while major flooding is expected to persist until the end of the week.

People in parts of the north-western town of Gunnedah have been told to evacuate as the area is hit with major flooding.

The Namoi River is predicted to peak near 8.2m early in the day.

In the 24 hours until Wednesday morning, the SES responded to 329 calls for help and performed 17 flood rescues.

Emergency Services Minister Steph Cooke said there were 122 flood warnings in place and hundreds of homes have been destroyed.

“I’m very worried about communities right across NSW,” she told ABC TV.

“There’s not a river system at the moment that’s not in flood or communities at risk.”

SES Chief Superintendent Dallas Burns said floodwaters at Forbes were slowly rising with water spreading throughout the town.

“We’re expecting that peak and that major flooding in Forbes to last a number of days,” he said, adding the flooding would continue in some river valleys and catchments for a number of months.

Fourteen people were rescued in Forbes at around 8pm on Tuesday night after the Plainsman Motel was inundated.

A rescue helicopter rescued an elderly couple, their daughter and two small dogs from a Forbes home that was threatened by rising waters about 10pm.

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

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, east of Forbes, early on Monday, devastating the town of 800 people.

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

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

Chambers, her husband, their three children and her parents eventually found a truck trailer to perch on.

They stayed there for six hours before a fire truck delivered them to the evacuation centre at the showground, from where they were flown to Orange.

“It’s devastating. Anything that is a memory is gone,” Chambers told AAP.

Eugowra 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”.