Man's body found in NSW floodwaters

The body of a man flung out of a ute and into a flooded NSW stream has been found as the search for his mate continues.

The pair were in the rear tray of the vehicle when it was driven onto a flooded causeway at Prestons Creek in the Southern Tablelands on Monday night.

Two men inside the cabin escaped and swam to safety but the other two men were taken downstream with the vehicle, police say.

Police divers on Thursday afternoon found a man's body, which is yet to be formally identified.

It comes as farmers face "devastating" losses across central NSW as dangerous flooding continues to hit the state's agricultural region and some residents ignore evacuation orders.

In the wheatbelt town of Forbes in the state's central west, some 600 people were told to evacuate their homes by 4pm on Thursday as rising waters threaten to cut off properties and strand residents.

Cattle farmer Charles Laverty was busy sandbagging his property on the outskirts of Forbes with about one-third of his paddocks already underwater.

Continued flooding has hit inland communities hard, as farmers struggle to recover from repeated bouts of destruction to crops and livestock.

"A lot of (my neighbours) have given up on harvesting those areas, which is very expensive," Mr Laverty told AAP.

"The losses are going to be devastating for them."

Despite warnings from authorities the Lachlan River would reach levels on Friday not seen since 1952, locals remained unsure how the peaks would hit the landscape due to significant changes in infrastructure.

"No one really knows what's going to happen," Mr Laverty said.

Some residents in the evacuation zone in Forbes opted to stay in their homes despite urgent warnings from the SES, telling residents in low-lying parts of Forbes to leave before nightfall.

Some locals made other preparations, including sourcing generators and bottled water in case they lost access to power and plumbing, Parkes-Forbes NSW Farmers Association vice-chairman Gavin Tom said.

"The problem isn't so much whether the house gets inundated - it's more if the services get affected by the floods," Mr Tom told AAP.

Record flooding is forecast in Forbes on Friday night when the Lachlan River is expected to peak, NSW SES Zone Commander Ben Pickup said.

He said peaks would continue through to Saturday morning.

"I really encourage the community of Forbes - please listen to the warning information," he said.

"Please, please follow that messaging."

Emergency Services Minister Steph Cooke said she understood the exhaustion felt by communities across central and southern NSW, but warned flooding would continue across inland catchments in coming days.

"Everyone is flood-weary but we need to keep working through this," she told reporters on Thursday.

"We are continuing to see peaks roll through the system even though there isn't water falling from the sky at the moment."

Major flooding on the Lachlan River on Thursday is causing inundations in the town of Nanami, and major flooding continues further downstream at Condobolin, with the river not expected to fall for weeks.

The Murrumbidgee River has also burst its banks, with major floods peaking at Gundagai on Wednesday night, and major peaks possible at Wagga Wagga on Thursday night.

Ms Cooke expressed her sympathies for the Gunnedah community, which has been hit by seven floods in recent weeks, and Wagga Wagga, which faces its fourth inundation since August.

Renewed, moderate flooding is also occurring at Albury and Corowa on the Murray River after widespread falls.

Premier Dominic Perrottet emphasised the warning that "if it's flooded - forget it".

"You wouldn't drive into a bushfire, don't drive into floodwaters," he said.