25/09/2016 8:01 AM AEST | Updated 25/09/2016 12:17 PM AEST

NSW Floods: Forbes Residents Urged To Evacuate

Major flooding is set to hit the NSW town of Forbes.

James Brickwood/Fairfax Media

Residents in the NSW central west town of Forbes are bracing for the worst flood in more than 60 years, with more than 1000 people fleeing to evacuation centres as waters in the region continue to rise.

The NSW State Emergency Service (SES) said on Sunday morning that major flooding was occurring at Forbes Iron Bridge, Cottons Weir and Jemalong, with peaks expected to hit levels similar to those in August 1990.

Bureau of Meteorology (BoM) hydrologist Hugh Bruist said the waters could rise even higher, possibly to levels not seen since 1952.

"It all depends on how we go during the day and the peak isn't due until late this afternoon maybe tonight," he told Macquarie Radio.

BoM said the Lachlan River was expected to peak between 10.65 and 10.70 metres at Forbes Iron Bridge on Sunday night, causing significant flooding. The river was forecasted to reach 7.4m at Cottons Weir on Monday night, and 8.3m at Jemalong on Tuesday.

Around 100 homes have already been inundated in the area, the ABC reports, with farmers preparing for heavy losses from the extreme weather.

The SES is urging residents in certain areas of Forbes to evacuate ahead of the town potentially being cut in two by flood water later this weekend.

Five Australian Defence Force (ADF) troop carriers reportedly arrived in the town on Saturday to offer their support if needed.

There is more rain forecast for the area on Sunday, with the big risk to Forbes residents coming from water running from the Lachlan River down into Lake Forbes.

SES Acting Commissioner Mark Morrow said there were high risks in staying in the area, warning that the flooding could last for up to 5 days.

"Three to five days is a long time to go without essential goods ... Flood water has a lot of stuff in it that's not nice, there is chemicals from properties, dead livestock in the area. We prefer people to leave," he told the ABC.