Work is under way to replace a single-lane bridge that spans the Murrumbidgee River east of Wagga.
The Mundarlo Bridge is inundated when more than 32,000 megalitres are recorded at Wagga, and when closed, leads to a 120-kilometre detour for traffic crossing the river.
A new 110-metre bridge will be 3.7 metres higher, able to remain open during flows of up to 100,000 megalitres per day, and carry two lanes of traffic.
The need to upgrade the bridge was identified during the early development stages of the NSW government's Reconnecting River Country program.
The state government is leading the project while the federal government is providing $30.7 million in funding.
NSW Water Minister Rose Jackson said the community "deserves infrastructure they can rely on, not a bridge that disappears the moment the Murrumbidgee River rises."
"When the river rises, people shouldn't be cut off from work, school or other essential services," she said.
"This new bridge will ensure safer, more reliable access year-round, while still supporting the region's farming and river systems."
Federal Environment and Water Minister Murray Watt said the new bridge would "deliver much needed reliability for locals, farmers and freight operators who depend on this crossing every day, while continuing to encourage healthy environmental flow."
The old bridge will remain open while crews build the new one slightly upstream, and will be demolished once the new structure is completed and approaches are realigned.
NSW-based Saunders Civilbuild has been awarded the contract to finalise the bridge design and undertake the construction works.
Practical construction is set to be completed by December and commissioned in early 2027.
