The Dry River Bridge on the Princes Hwy at Quaama will be closed for essential maintenance work to be carried out.
A Transport for NSW spokesperson said bearings will be replaced on the bridge, located 30km north of Bega, to increase its life and reduce further maintenance costs.
"The Princes Hwy carries a large amount of traffic so it is important to keep the bridge safe for all road users," the spokesperson said.
To prepare for the planned work, crews will be testing equipment at night on Sunday, July 21 between 7pm and 11pm, weather permitting.
This is in addition to daytime road maintenance activities that have been underway since late June.
The spokesperson said no vehicles or pedestrians will be permitted to cross the bridge during this time for the safety of workers and road users.
"The full closure is required to test the jacking system which will raise and lower the bridge during maintenance work next month," the spokesperson said.
Work to replace the bearings will be carried out from Sunday, August 4 for two weeks on weeknights from Sundays to Thursdays, between 7pm and 5am, weather permitting.
The spokesperson said Dry River Bridge will need to close to traffic each night during this two-week period between 7pm and 9pm while the bridge is lifted to allow crews to safely work under the structure, and then from 3am and 5am each morning as the bridge is brought back down to its standard height.
"No traffic will be able to travel over the bridge during the closures," the spokesperson said.
"Motorists are advised to plan their journey to avoid lengthy delays.
"Emergency services located north of Dry River Bridge will be able to access Quaama during the closure periods and in the event of an emergency, residents should always dial triple zero (000).
"Outside of these closures, Dry River Bridge will operate as a single lane during work hours under stop/slow traffic control.
"Single lane closures may also be in place outside of work hours as required and motorists are advised to check electronic message boards for additional traffic changes"
For the latest traffic updates call 132 701, visit livetraffic.com or download the Live Traffic NSW App.