Evacuation orders issued for Gunnedah, Wagga Wagga and Forbes as flood risk builds in NSW

Evacuation orders are being issued for hundreds of residents in Gunnedah, Wagga Wagga and Forbes in New South Wales as river levels rise once again.

An urgent evacuation order has been issued for residents in at least five streets in North Gunnedah to leave by 9pm after heavy rain caused renewed rises in the Namoi River.

More than 700 residents in North Wagga Wagga as well as those inside the levee and residents in the area of Gumly Gumly have been ordered to evacuate by Friday at 8am.

The Murrumbidgee River is expected to peak at 9.6 metres on Thursday morning, cutting off many homes and businesses.

Those protected by the 9.8m North Wagga levee will be cut off if the river reaches the predicted height of 9.6m, with further rises possible.

At Forbes, in the state's Central West, residents in large parts of the town have been told to evacuate before 4pm Thursday, with the Lachlan River expected to reach the major flood level again.

Floodwater could rise to levels not seen in 70 years in Forbes on Friday.

The warning comes weeks after hundreds of residents, including in the central business district, were ordered to evacuate due to the flood risk.

The State Emergency Service (SES) again urged people to assist with sandbagging through to the end of the week.

North Wagga bracing

The State Emergency Service (SES) said the levee at North Wagga was not expected to break at this stage, but the ability to rescue people was challenged by the river reaching the major level.

"At that height they only have one road in and out, and once it gets to 9.6m the water will inundate that road and then we lose all access to that community,"  SES southern zone commander Benjamin Pickup said.

He said the North Wagga area could be cut off for a number of days.

"Given how slow we're seeing the river peaks fall from the previous flood events, there could be at least four to five days where there's potential to be cut off," Mr Pickup said.

"While we see it usually drop off quite quick, given the amount of floodwater and that high river level, it will take time for the peak to drop."

North Wagga resident Fiona Ziff is preparing for the fourth flood peak in two months.

She said despite the prolonged flooding, this warning had come as a surprise.

"We've sort of been on high alert for the last month or two, that's for sure, but the previous notices were isolation only — we were going to isolate for 24 hours," Ms Ziff said.

"So personally I wasn't really expecting the evacuation order.

Central West on alert

Spills from the Wyangala Dam, which feeds into the Lachlan River in the central west, had increased to 125,000ML a day.

Major flooding on the Belubula River at Canowindra resulted in water lapping at the edge of buildings on the town's main street.

The SES supplied sandbags to residents and business owners in the lead up to the flood peak on Tuesday afternoon.

The river level hit 4.94 metres, which exceeded the floods of 2010.

At nearby Eugowra, major flooding on the Mandagery Creek caused water to flow into streets and yards, but there were no reports of flooded homes.

The Macquarie River at Bathurst also reached major flood level of 5.6 metres.

Water levels have receded to moderate flooding however farmland and some roads remain underwater.

Gundagai, on the Murrumbidgee River downstream of the Burrinjuck Dam, has been in major flood since Tuesday.

There are warnings the town could experience its worst flood in 10 years, however no homes are currently under threat.

Further south releases from Hume Dam, which is at 96 per cent capacity, are mixing with floodwater from Victorian rivers to create renewed major flooding along the Murray River.

The Murray Darling Basin Authority, which operates the dam, said releases had increased to 75,000ML in response to inflows peaking at 100,000ML early Tuesday morning.

The authority said those releases, combined with inflows from the Kiewa River downstream, could potentially cause major flooding at Albury in coming days.

'Unprecedented' dam challenges

One of the state's most senior water executives said it had been "extremely challenging" to manage dams amid ongoing rain and flooding.

Spills from Burrinjuck Dam west of Canberra peaked at 120,000 megalitres a day overnight before progressively dropping rapidly to 70,000ML late morning.

All but two of the state's regional dams were above capacity and WaterNSW's executive manager of operations, Ronan Magaharan, said the past few months had been "unprecedented".

He said dams were being monitored daily to ensure they were operating safely.

"It really is challenging for us to get the storage down to a level where that rain, when it does come again, we are able to capture it all and not make releases," he said.

"It is really challenging for the team to get that right and not contribute to floods downstream."

Search for two men resumes

A search has resumed for two men who were swept out of a ute in floodwater near Boorowa on the NSW southern Tablelands.

Police said the men were believed to be in the tray of the ute that was trying to cross a flooded causeway at Bevendale on Monday night.

Two men in the cabin were able to escape.

Editor's note 3/11/22: This article initially referred to water overflowing from dams as releases. It has been amended to reflect that they were instead spills.