Flooding in Forbes, in central west NSW, has fallen below major levels, with rescue workers shifting their focus to Euabalong and Condobolin.
A 4-kilometre makeshift levee of dirt and sandbags, which has become known as "the great wall of Condo", is protecting the Condobolin central business district from Lachlan River floodwater, which is steady at 7.57 metres.
"We're working with the local emergency management committee there to establish an evacuation shelter," SES incident controller Ken Murphy said.
"Our river systems and our dam systems are full to capacity so any additional water into those will cause us some issues."
It is already the town's worst flood on record, with a possible peak of 7.8m expected on Wednesday.
"Our crews from Singapore, who we'll be sending over this morning, will be doing orientation in that area there and also doing some resupply work," Mr Murphy said.
Meanwhile in nearby Euabalong, floodwater flowing down the Lachlan River cut off evacuation routes and partially collapsed a makeshift levee.
It resulted in the State Emergency Service issuing a shelter now emergency warning overnight, however conditions have de-escalated and residents have been urged to monitor the situation.
Upstream at Forbes, river levels fell below the major flood level to 10.42m, but hundreds of people remain under an evacuation order.
Several other major river catchments are experiencing major flooding in what authorities say has become the state's largest ever flood response.
The SES said the town of Deniliquin was also a focus with the Edward River expected to exceed the major level early next week.
There are 101 flood alerts in place across the state, with 21 of those at emergency level.
SES crews rescued nine people and received more than 260 calls for flood assistance across NSW in the 24 hours to 3pm on Sunday.
On top of that, there were 245 calls for storm assistance after damaging winds saw roofs fly off in the state's south west and fallen trees and powerlines in the south east and Sydney.
The flood disaster again became deadly this week after two people died in flash flooding at Eugowra.
Police discovered a body on Saturday believed to be 85-year-old Ljubisa 'Les' Vugec, who has been missing since the catastrophic flash flood hit the small town on Monday.
The discovery came three days after 60-year-old Diane Smith's body was found.
Emergency crews are helping some Eugowra residents return to their homes, after about 90 per cent of properties were either damaged or destroyed.
NSW Premier Dominic Perrottet said an operation centre would be set up in the town tomorrow.
"I think we've learned from the past; the response is so much better and the recovery as well. The clean up is underway, it's an incredibly challenging time," Mr Perrottet said.
Personnel have been flown in from Singapore and New Zealand to relieve exhausted crews, with authorities warning the response to immediate threats of inundation and ongoing isolation could go on for months.
Woman fined
A woman has been fined after being rescued from floodwater in the state's north on Friday.
Police said the 56-year-old ignored a road closure sign while travelling on Culgoora Road at Wee Waa about 8pm.
She became trapped after her car entered floodwater and needed to be rescued before the car was extracted using specialist equipment.
All roads into the town remain closed due to major flooding in the Namoi River.
Regional emergency operations controller Danny Sullivan said anyone who ignored road signs in order to drive through floodwater could expect to be fined.
"Those who drive into floodwaters put their own lives at risk, as well as the lives of the emergency services who respond to assist them," Superintendent Sullivan said.
"We don't need the added danger of entering floodwater to rescue people who have decided to take a risk."
